واﻟ واﻟ  ﻟﻠ  اﻟ  اﻟﻬ 
Saudi Standards, Metrology and Quality Org. (SAS O) 
 
      
 
 
 
 
Final Draft Standard    
 
  
SASO/FDS 31827/2020  
 
  
School buses - General requirements 
 
 
 
 
ICS: 43.080.20 
 
This document is a draft Saudi Standard circulated for comments . It is, therefore, 
subject to alteration and modifi cation and may not be referred to as a Saudi 
Standard until approved by SASO . SASO S TANDAR D SASO/FDS 31827/2020
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 Conte nts 
1- Scope....................................................... ............................................................... ................ 3 
 
2- Complementary References ............................................................. ................................... 3 
 
3- Terms and definitions ............................................... ........................................................... 6 
 
4- Classification ............................................. ............................................................... ............ 7 
 
5- Technical requirements ............................................................... ........................................ 7 
5.1 General .............................................................. ............................................................... .... 8 
5.2 Dimensions and weights ............................................................... ....................................... 8 
5.3 Frame and Body ........................................................... ........................................................ 8 
5.4 Fuel System................................................ ............................................................... ....... 10 
5.5 Seating.................................................... ............................................................... ........... 11 
5.6 Alternator ............................................................... .......................................................... 12 
5.7 Batteries ................................................. ............................................................... ........... 12 
5.8 Brakes .................................................... ............................................................... ........... 13 
5.9 Exhaust System  .............................................................. .................................................. 14 
5.10 Sound signaling device ............................................................... ................................... 15 
5.11 Front bumper.............................................. ............................................................... ..... 15 
5.12 Rear bumpe r ............................................................. ...................................................... 15 
5.13 Shock absorbers .......................................... ............................................................... .... 16 
5.14 Drive shaft............................................... ............................................................... ........ 16 
5.15 Engine ............................................................... ............................................................. 1 6 
5.16 Steering System .......................................... ............................................................... .... 16 
5.17 Tyres and wheels.......................................... ............................................................... ... 17 
5.18 Turning radius ............................................................ .................................................... 17 
5.19 Windshield defrosting and defogging systems .............................................................. 18 
5.20 Windshield wiping a nd washing system...................... ................................................... 18 
5.21 Front fenders ............................................................... ................................................... 18 
5.22 Service door ............................................. ............................................................... ....... 18 
5.23 Emergency exits ............................................................. ................................................ 20 
5.24 Floor covering ............................................................ .................................................... 22 
5.25 Insulation................................................ ............................................................... ......... 23 
5.26 Interior.................................................. ............................................................... ........... 23 
5.27 Lamps, reflectors, and signals............................ ............................................................ 23  
5.28 Rearview ................................................. ............................................................... ........ 26 
5.29 Stabilit y ............................................................. ............................................................. 2 7 
5.30 Cooling system............................................ ............................................................... .... 28 
5.31 Safety Belts ............................................................. ....................................................... 28 
5.32 Steps ............................................................ ............................................................... .... 28 SASO S TANDAR D SASO/FDS 31827/2020
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 5.33 Stirrup .................................................. ............................................................... ........... 29 
5.34 Stop signal arm .......................................... ............................................................... ..... 29 
5.35 Crossing arm .............................................................. .................................................... 30 
5.36 Sun shield................................................ ............................................................... ........ 30 
5.37 Undercoating.............................................. ............................................................... ..... 31 
5.38 Ventilation............................................... ............................................................... ........ 31 
5.39 Wheel housing ............................................ ............................................................... .... 31 
5.40 Windshield and windows ......................................................... ...................................... 32 
5.41 Electrical components ............................................................. ....................................... 33 
5.42 Side intrusion ............................................................... .................................................. 34 
5.43 Speedometer and odometer devise s ............................................................. .................. 34 
5.44 Controls, telltales and indicators device s ............................................................. .......... 35 
5.45 Vehicle identification number (VIN) ...................... ....................................................... 36 
5.46 Speed limiters............................................ ............................................................... ...... 36 
5.47 Air bags ............................................................ .............................................................. 36 
5.48 Transmission, starter interlock, and transmission braking effect .................................. 36 
5.49 Air cleaner............................................... ............................................................... ........ 37 
5.50 Suspension systems........................................ ............................................................... . 37 
5.51 Towing attachment points.................................. ............................................................ 37  
5.52 Hinges ............................................................... ............................................................. 3 7 
5.53 Accelerator control....................................... ............................................................... ... 37 
5.54 Passenger compartment air conditioni ng ............................................................ ........... 38 
5.55 Exterior noise level ..................................... ............................................................... .... 39 
5.56 Limits of gaseous pollutants ............................. ............................................................. 3 9 
 
6- Safety equipments ............................................................... ............................................... 40 
 
7- Information of vehicle..................................................... ................................................... 41 
 
8- Owner’s manual (Operating Instructions) ............................................................... ....... 41 
 
9- Identification......... .............. ............... ........... ...................... .............. .............. ............. ....... 42 
 
10- School bus requirements for persons with special health care needs.......................... 43 
 
Annex (A) Roof hatch performance test .............................................................. .................... 51 
 
Annex (B) Side Intrusion Test ............................................................... .................................. 53 
 
Bibliography  ................................................. ............................................................... ........... 54 SASO S TANDAR D SASO/FDS 31827/2020
3 
 School buses - General requirements 
 
1- Scope 
This Standard specifies the technical requirements for school b uses intended to transport 
students to ensuring high levels of safety and environmental protection from gaseous emissions. 
 
2- Complementary References 
2.1 SASO GSO 34 "Lead-acid starter batteries used for motor cars a nd internal combustion 
engines". 2.2 SASO GSO 35 "Methods of test for lead-acid starter batteries u sed for motor cars and 
internal combustion engines". 
2.3 SASO GSO 36 "Motor vehicles - Methods of test for impact stren gth - Part 1: Frontal 
impact". 2.4 SASO GSO 37 "Motor vehicles - Methods of test for impact stren gth - Part 2: Moving 
barrier rear impact". 
2.5  SASO/FDS 31843 "School buses - Rear crash test using moving b arrier".(FMVSS 
571.301) 
2.6 SASO GSO 38 "Motor vehicles - Methods of test for impact stren gth - Part 3A: Side 
Impact". 
2.7 SASO GSO 1707 "Motor vehicles - Methods of test for impact str ength - Part 3B: Moving 
barrier side impact". 
2.8 SASO/FDS 31832 "School buses - Roof strength".(FMVSS 571.22 0) 
2.9 SASO GSO 40 "Motor vehicles - Impact strength". 
2.10 SASO GSO 647 "Multi-purpose vehicles, trucks, buses and traile rs tyres - Part 3: General 
requirements". 
2.11 SASO GSO 646 "Multi-purpose vehicles, trucks, buses and traile rs tyres - Part 2: Methods 
of test". 2.12 SASO 469 "Motor vehicles - Dimensions and weights". 
2.13 SASO GSO 97 "Motor vehicles - Safety belts". 
2.14 SASO GSO 96 "Motor vehicles - Methods of testing safety belts" . 
2.15 SASO GSO 289 "Road vehicles retro - Reflective number plates a nd its methods of test". 
2.16 SASO GSO 99 "Road vehicles - Sound signaling devices - Technic al specification". 
2.17 SASO GSO 136 "Motor vehicles - Engine radiator ". 
2.18 SASO GSO 135 "Motor vehicles - Methods of test for engine radi ator". 
2.19 SASO GSO 144 "Motor vehicles - Appeasable limits of pollutants  e m i t t e d  t o  t h e  
atmosphere from heavy-duty diesel engine vehicles". 2.20 SASO GSO 145 "Motor vehicles - Methods of testing for pollutan ts emitted from heavy- 
duty diesel engine vehicles - Part 1: Determinations of exhaust  gaseous pollutants". 
2.21 SASO GSO 146 "Motor vehicles - Methods of testing for pollutan ts emitted from heavy-
duty diesel engine vehicles - Part 2: Determination of smoke". 
2.22 SASO GSO 1040 "Motor vehicles – Allowable limits of pollutants  emitted to the 
atmosphere from light-duty diesel engine vehicles". 2.23 SASO GSO 1041 "Motor vehicles - Methods of testing for polluta nts emitted from light 
duty diesel engine vehicles - Part 1: Determination of exhaust gaseous pollutants". SASO S TANDAR D SASO/FDS 31827/2020
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 2.24 SASO GSO 1042 "Motor vehicles - Methods of testing for polluta nts emitted from light- 
duty diesel engine vehicles - Part 2: Determination ". 
2.25 SASO GSO 1680 "Motor vehicles - Allowable limits of gaseous po llutants emitted to the 
atmosphere from unleaded gasoline engine vehicles". 2.26 SASO GSO 1681 "Motor vehicles - Allowable limits of gaseous po llutants emitted to the 
atmosphere from unleaded gasoline engine vehicles - Part 1: Det ermination of exhaust gaseous 
pollutant a cold start". 
2.27 SASO GSO 1682 "Motor vehicles - Allowable limits of gaseous po llutants emitted to the 
atmosphere from unleaded gasoline engine vehicles - Part 2: Det ermination of exhaust carbon 
monoxide at idle speed". 
2.28 SASO GSO 1683 "Motor vehicles - Allowable limits of gaseous po llutants emitted to the 
atmosphere from unleaded gasoline engine vehicles - Part 3: Det ermination of evaporative 
emission (hydrocarbons) from the fuel system". 
2.29 SASO GSO 1684 "Motor vehicles - Allowable limits of gaseous po llutants emitted to the 
atmosphere from unleaded gasoline engine vehicles - Part 4: Det ermination of gaseous 
pollutants emitted from engine crankcase". 
2.30 SASO GSO 1685 "Motor vehicles - Allowable limits of gaseous po llutants emitted to the 
atmosphere from unleaded gasoline engine vehicles - Part 5: Det ermination of durability of 
pollution control equipment". 
2.31 SASO GSO 1624 "Motor vehicles - Noise emissions". 
2.32 SASO GSO 1625 "Motor vehicles - Speed limiters - Part 2: Techn ical requirements". 
2.32 SASO GSO 1626 "Motor vehicles - Speed limiters - Part 3: Metho ds of test". 
2.33 SASO/FDS 31830 "School buses - School buses - Pedestrian safet y 
devices".(FMVSS 571.131) 
2.34  SASO/FDS 31834 "School buses -  body joint strength".(FMVSS 57 1.221) 
2.35  SASO/FDS 31835 "Road vehicles - Speedometer and odometer devi ses". (ECE 39/2018) 
2.36  SASO/FDS 31836 "Controls, tell-tales and indicators". (ECE 12 1:2015 & FMVSS 
571.101) 
2.37  SASO/FDS 31837 "Road vehicles - Windshield defrosting and def ogging systems". 
(FMVSS 571.103) 
2.38  SASO/FDS 31839 "Road vehicles - Windshield wiping and washing  systems". 
(FMVSS 571.104) 
2.39 SASO/FDS 31840 "Road vehicles - Transmission shift position se quence, starter 
interlock and transmission braking effect". (FMVSS 571.102) 
2.40  SASO/FDS 31841 "Road vehicles - Impact protection for the dri ver from the 
steering control system". (FMVSS 571.203) 
2.41  SASO/FDS 31842 "Road vehicles - Flammability of interior mate rials". (FMVSS 
571.302) 
2.42 SASO GSO 1677 "Motor vehicles - Laminated safety glass". 
2.43 SASO ISO 3537 "Road vehicles - Safety glazing materials - Mech anical tests". 
2.44 SASO ISO 3538 "Road vehicles - Safety glazing materials - Test  methods for optical 
properties". 
2.45 SASO ISO 3917 "Road vehicles - Safety glazing materials - Test  methods for resistance 
to radiation, high temperature, humidity, fire and simulated we athering". SASO S TANDAR D SASO/FDS 31827/2020
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 2.46 SASO ISO 13837 "Road vehicles - Safety glazing materials - Met hod for the determination 
of solar transmittance". 
2.47 SASO GSO 1780 "Motor vehicles - Vehicle identification number (VIN) - Requirements". 
2.48 SASO GSO 1781  "Motor vehicles -  Vehicle identification numbe r (VIN)  -  World 
manufacturer identifier (WMI)". 2.49 SASO GSO 1782 "Motor vehicles - Vehicle identification number (VIN) - Location and 
attachment". 
2.50 SASO GSO ISO 3911 "Wheels and rims for pneumatic tyres - Vocab ulary, designation 
and marking". 2.51 SASO GSO ISO 3894 "Road vehicles - Wheels/rims for commercial vehicles - Test 
methods". 
2.52 SASO GSO ISO 4209-2 "Truck and bus  tyres and rims (metric seri es) - Part 2: Rims". 
2.53 SASO GSO ISO 1585 "Road vehicles - Engine test code - Net powe r". 
2.54 ASTM B117 "Standard Practice for Operating Salt Spray (Fog) Ap paratus". 
2.55 ASTM D750 "Standard Practice for Rubber Deterioration Using Ar tificial Weathering 
Apparatus". 
2.56 ASTM D1894 "Standard Test Method for Static and Kinetic Coeffi cients of Friction of 
Plastic Film and Sheeting". 
2.57 ASTM D2047 "Standard Test Method for Static Coefficient of Fri ction of Polish-Coated 
Flooring Surfaces as Measured by the James Machine" 
2.58 ASTM D4060 "Standard Test Method for Abrasion Resistance of Or ganic Coatings by the 
Taber Abraser". 2.59 ASTM E308 "Standard Practice for Computing the Colors of Objec ts by Using the CIE 
System". 
2.60 ASTM E810 "Standard Test Method for Coefficient of Retroreflec tion of Retroreflective 
Sheeting Utilizing the Coplanar Geometry". 2.61 ASTM E1164 "Standard Practice for Obtaining Spectrometric Data  f o r  O b j e c t - C o l o r  
Evaluation". 2.62 SASO GSO ECE 46 "Uniform provisions concerning the approval of  devices for indirect 
vision and of motor vehicles with regard to the installation of  these devices". SASO S TANDAR D SASO/FDS 31827/2020
6 
 3- Terms and definitions 
For the purposes of this standard, the following terms and defi nitions are applied: 
3.1 School bus 
A specially constructed vehicle that is designed to carry more than ten persons to and from 
school, university or related events. 
3.2 School bus for persons with disabilities 
A school bus that is designed to carry persons with disabilitie s and special health care needs to 
and from school or related events. 
3.3 Gross axle weight rating (GAWR)  
The value specified by the vehicle manufacturer as the load- ca rrying capacity of a single axle 
system, as measured at the tire-ground interfaces. 
3.4 Gross vehicle weight (GVW)  
The loaded weight of a single vehicle, as measured at the tire- ground interfaces. 
Note: The loaded weight is the sum of the unloaded vehicle weig ht, rated cargo load, 54 kg times the number of 
designated seating positions, and 68 kg for the driver. 
3.5 Gross vehicle weight rating (GVWR)  
The value specified by the vehicle manufacturer as the load- ca rrying capacity of a single 
vehicle, as measured at the tire-ground interfaces. 
3.6 Curb weight 
The weight of a vehicle with standard equipment; maximum capaci ty of engine fuel, oil, and 
coolant; and, if so equipped, air conditioning and additional w eight optional engine. 
3.7 Fixed vehicle structure 
A structure that is attached to a vehicle and cannot be removed  without tools. 
Note: Wheelchairs and wheelchair tie-downs are not considered fixed structures. 
3.8 Mobility aid 
A device used from persons with disabilities and special health  care needs to facilitate transport, 
in a seated posture. 
Note: Examples include manual and powered wheelc hairs. 
3.9 Person with a disabi lity 
A person who, because of a mobility impairment, requires access ible transportation. SASO S TANDAR D SASO/FDS 31827/2020
7 
 4- Classification 
4.1 Type A 
A conversion or body constructed upon a cutaway front section v ehicle with an original 
equipment manufacturer chassis, supplied with a left side drive r’s door and service door is 
behind the front wheels. 
4.1.1 Type A1 
A vehicle with a GVWR of 4500 kg or less. 
4.1.2 Type A2 
A vehicle with a GVWR over 4500 kg. 
4.2 Type B 
A conversion or body constructed and installed upon a van, a fr ont section vehicle chassis, or a 
stripped vehicle chassis, having a GVWR of more than 4500 kg. 
Most of the engine is beneath and/or behind the windshield and beside the driver’s seat. 
The service door is behind the front wheels. 
4.3 Type C 
A body installed upon a flat back cowl chassis, having a GVWR o f more than 4500 kg. 
The entire engine is in front of the windshield and the service  door is behind the front wheels. 
4.4 Type D 
A body installed upon a chassis, having a GVWR of more than 450 0 kg. The engine mounted 
in one of the following positions: 
a) Behind the windshield and beside the driver’s seat; 
b) At the back of the bus behind the rear wheels; or 
c) midship between the front and rear axles. The service door is ahead of the front axle. 
 
 
5- Technical requirements 
5.1 General 
5.1.1  The effectiveness or integrity of any major safety system (e.g . emergency exit opportunity, 
fuel system integrity) shall not be compromised. 
5.1.2  The safe environment of the bus interior shall not be diminish ed. 
5.1.3  There shall be no additional risk to students during entry or egress or while in near the 
loading zone. 
5.1.4  The new technology, equipment, or components shall result in e nhancement in the 
efficiency and safety of the bus, an enhancement in the safety or experience of the occupants 
and pedestrians in the vicinity of the bus, or an aid to the pe rformance of the driver’s tasks. 
5.1.5  The exterior body of school bus shall be yellow according to t he color grade number 
RAL1018ZinkgelbGL841 and no other color interference. 
5.1.6  School buses may be equipped with a DAB+ and AM/FM/audio and/or public address 
system having interior and exterior speakers. 
5.1.7  School buses shall be equipped with a safety switch at the rea r of the bus (inside the 
bus) to ensure that the bus is clear of passengers before turni ng off the engine. 
5.1.8  Articulated buses and double decker buses shall not be used as  school buses. 
 
 
 SASO S TANDAR D SASO/FDS 31827/2020
8 
 5.2 Dimensions and weights 
5.2.1 Aisles 
5.2.1.1  The minimum width of the aisle between left-side and right-sid e seats leading to the 
rear center emergency door or rear center emergency window shal l be 350 mm. 
5.2.1.2  In the case of Type D bus with the engine inside the front of the body, the minimum 
distance between any structure (w hether fixed or movable) at th e rear of the entrance stepwell 
and the engine cover shall be 300 mm, measured horizontally at any vertical point between the 
floor level and the height of the top surface of a seat cushion . 
5.2.2 Bus length and width 
5.2.2.1  The overall length of school bus shall not exceed 12.50 m when  measured from bumper 
to bumper. 
Note: Accessories are excluded from this measurement, for more details see the Saudi Standard SASO 496. 
5.2.2.2  The outside body width of buses shall not exceed 2.6 m, exclud ing accessories. 
Note: Accessories are excluded from this measurement, for more details see the Saudi Standard SASO 496. 
5.2.3 Inside height 
5.2.3.1  In the case of Type A1 bus, the inside body height shall be a minimum of 1650 mm 
measured metal to metal, at any point on the longitudinal cente rline from the front vertical bow 
to the rear vertical bow. 
5.2.3.2  In the case of Type A2, B, C, and D buses, the inside body hei ght shall be a minimum 
of 1800 mm, measured at any point on the longitudinal centerlin e from the front vertical bow 
to the rear vertical bow. 
Note: The inside height measurement shall not include air condi tioning equipment. 
5.2.4 Steps height 
5.2.4.1  The first step at the service door shall be 250 to 400 mm from  the ground. 
5.2.4.2  The service door entrance may be equipped with a stepwell that  has more than two than 
two steps. 
5.2.4.3  Step risers shall not exceed a height of 250 mm. 
Note: The differential may be increased by the thickness of the floor covering used on steel floor. 
5.2.5 Seating  
5.2.5.1  The minimum width of the seat shall be 400 mm. 
5.2.5.2  The minimum depth of a seat shall be 380 mm. 
5.2.5.3  The minimum seat back height shall be 610 mm above the seating  reference point. 
5.2.5.4  The minimum seat height shall be 350 mm from the ground. 
5.2.5.5  The minimum between the back seats shall be 650 mm. 
 
5.2.6 Weights  
5.2.6.1  All school buses shall not exceed the maximum allowable gross vehicles weight (GVW) 
and gross axle weight (GAW) according to SASO 469. 
 
 
5.3 Frame and Body 
5.3.1 Frame 
5.3.1.1  At a minimum, the frame or equivalent shall have design and st rength characteristics 
that correspond to those that are standard for trucks with the same general load characteristics 
and that are used for highway service. SASO S TANDAR D SASO/FDS 31827/2020
9 
 5.3.1.2  Holes in the top or bottom flanges of the frame side rail shal l not be permitted (other 
than those provided in the original chassis frame). 
5.3.1.3  Frames shall not be modified for the purpose of extending the wheel base. 
5.3.1.4  When frame side members are used in Type B, C, and D buses, th ey shall be a one-piece 
construction between the front hanger brackets of the front spr ing and the rear hanger brackets 
of the rear spring. 
5.3.2 Body 
5.3.2.1 General 
5.3.2.1.1  All openings between the chassis and passenger compartment sha ll be sealed to 
prevent exhaust gases from leaking into the passenger compartme nt. 
5.3.2.1.2  The floor shall have an overlay of 13 mm covering with a surfa ce suitable for foot 
traffic The overlay shall be securely fastened to the floor and have th e following performance 
characteristics: 
a) A minimum bearing strength of 4.5 MPa; and 
b) A minimum R value of 0.58. 
5.3.2.1.3  The aisle shall be on the same level as the bus floor. 
5.3.2.1.4  The external surface of a school bus shall be free from any pr ominent sharp or rotating 
parts that could cause road traffic risk. 
5.3.2.1.5  The chassis frame shall extend to the rear edge of the rear bo dy 
cross-membe r. 
Exce pt where chassis components interfere, the body of the bus shall be attached to the chassis 
frame at each main floor sill in a manner that prevents shiftin g or separation of the body from 
the chassis under severe operating condition. 
5.3.2.1.6  In the case of a Type C bus, the body front shall be attached and sealed to the chassis 
cowl in a manner that prevents entry of water, dust, and fumes through the joint between the 
chassis cowl and the body. 
5.3.2.1.7  Each school bus shall be provided with places at the front and  rear of the school 
bus  for  fixing  the  number  plates  according  to  dimension s  specified  in  Saudi  Standard 
SASO GSO 289. 5.3.2.2  In addition to meeting the requirements of Clauses 5.3.2.1.1 t o 5.3.2.1.3, the 
construction of the body of every Type A2, B, C, and D bus shal l meet the following 
requirements: 
5.3.2.2.1  The floor shall be constructed of steel at least 14 gauge or e quivalent. 
5.3.2.2.2  All metal except high-grade stainless steel or aluminum used i n construction of the 
bus body shall be zinc-coated or aluminum-coated or treated to prevent corrosion (includes 
structural members, inside and outside panels, door panels and floor sills). 
5.3.2.2.3  The metal so treated shall include parts such as structural me mber, inside and outside 
panels, floor panels, and floor sills, and shall exclude door h andles, grab handles, stanchions, 
interior decorative parts, and other interior plated parts. 
5.3.2.2.4  In addition to meeting the requirements of Clauses 5.3.2.2.2 a nd 5.3.2.2.3, all metal 
parts to be painted shall be: 
a) Chemically cleaned, etched, zinc phosphate coated, and zinc ch romate or epoxy 
primed (includes crossing control arm and stop arm); or 
b) Conditioned by an equivalent process. SASO S TANDAR D SASO/FDS 31827/2020
10 
 5.3.2.2.5  In fulfilling the requirements of Clauses 5.3.2.2.2 to 5.3.2.2 .4, particular attention shall 
be given to: 
a) Lapped surfaces; 
b) Welded connections of structural members; 
c) Cut edges; 
b) Punched or drilled hole areas in sheet metal; 
e) Closed or box sections; 
f) Unvented or undrained areas; and 
g) Surface subjected to abrasion during vehicle operation. 
5.3.2.2.6  As evidence that the requirements of Clauses 5.3.2.2.2 to 5.3. 2.2.4, have been met, 
samples of materials and section used in construction of the bu s body, when subjected to the 
1000 h salt spray test in accordance with ASTM B117, shall not lose more than 10% of the 
material by weight. 5.3.2.2.7  Each body panel joint (including small, curved, and complex jo ints) shall meet the 
technical requirements and test procedures according to SASO/FD S 31834 “School buses - 
body joint strength”. 
5.3.2.1.8  The whole design and construction of school buses, shall withs tand the impact forces 
to the front, rear, side and roof to reduce the likelihood of i njuries to the driver and passengers, 
as follows: 
a) All school buses with a gross vehicle weight (GVW) of 4500 or less according to Saudi 
Standard SASO GSO 40 when tested in accordance with SASO GSO 36 ” 
b) All school buses with a gross vehicle weight (GVW) of 4500 kg or less according to Saudi 
Standard SASO GSO 40 when tested in accordance with SASO GSO 37  
c) All school buses with a gross vehicle weight (GVW) over 4500 k g according to Standard 
SASO/FDS 31843 “School buses - Rear crash test using moving bar rier” 
d) All school buses with a gross vehicle weight (GVW) of 4500 kg or less according to Saudi 
Standard SASO GSO 40 when tested in accordance with SASO GSO 38 . 
e) All school buses with a gross vehicle weight (GVW) of 4500 kg or less according to Saudi 
Standard SASO GSO 40 when tested in accordance with SASO GSO 17 07. 
f) All school buses when tested in accordance with SASO/FDS 31832  “School buses - 
Roof strength”. 
 
 
5.4 Fuel Sy stem 
5.4.1  The fuel tank and its connections shall be securely placed and  installed in a manner that 
will become resist exposure to damage from vibration, impact, o r flammability. 
5.4.2  Each fuel tank fill pipe shall be provided with a securely clo sed cap at the pipe inlet. 
5.4.3  The design of the fuel tank position and its connections shall  be such that no fuel leaks 
occur when the bus is subjected to an impact test, as following : 
a) All school buses with a gross vehicle weight (GVW) of 4500 or less according to Saudi 
Standard SASO GSO 40 when tested in accordance with SASO GSO 36  
b) All school buses with a gross vehicle weight (GVW) of 4500 kg or less according to Saudi 
Standard SASO GSO 40 when tested in accordance with SASO GSO 37  SASO S TANDAR D SASO/FDS 31827/2020
11 
 c) All school buses with a gross vehicle weight (GVW) over 4500 k g according to Standard 
SASO/FDS 31843 “School buses - Rear crash test using moving bar rier” 
5.4.4  In the case of Type C buses, the fuel tank, fittings, or fuel lines between the fuel tank and 
the engine shall not extend above the chassis frame rail on the  portion of the chassis that is 
behind the cowl. 
5.4.5  The fuel fill hose assembly for all buses shall be entirely is olated from the passenger 
compartment to prevent fumes or fuel from penetrating the passe nger compartment and to 
protect any exposed components of the fuel fill hose assembly f rom damage. 
5.4.6   Fuel  tank  having  a  minimum  94-liter  capacity  shall  be   provided  by  the  chassis 
manufacturer. 
 
5.5 Seating  
5.5.1 Driver Seat 
5.5.1.1 The driver’s seat supplied by the body manufacturer shall be a high back seat. 
5.5.1.2  The seat back shall be adjustable to 15 degrees minimum, witho ut requiring the use of 
tools. 
5.5.1.3  The seat shall be equipped with a head restraint. 
Note: Type A buses may utilize the standard driver’s seat provided by the ch assis manu facturer. 
5.5.2 Passenge r Seating  
5.5.2.1  School bus  design  capacities shall  meet  the  technical req uirements according to 
Standard(1). 
5.5.2.2  Each seat leg shall be secured to the floor by bolts, washers and nuts and flange-head 
nuts may be used in lieu of nuts and washers. 
5.5.2.3  All seat frames attached to the seat rail shall be fastened wi th two or more bolts, washers 
and nuts, or with flange head nuts. 
5.5.2.4  All school buses shall be equipped with restraining barriers. 
5.5.2.5  A flip-up seat may be installed at any side emergency door and  shall be free of sharp 
projections on the underside of the seat bottom and shall be pa dded or contoured to reduce the 
possibility of clothing being snagged. 
5.5.2.6  A flip-up seats shall be constructed to prevent passenger limb s from becoming entrapped 
between the seat back and the seat cushion when the seat is in the upright position. 
5.5.2.7  The seat cushion shall be designed to rise to a vertical posit ion automatically when it is 
not occupied. 5.5.3 
Cove ring material 
5.2.3.1  All seat and restraining barrier covering shall be made of mat erial that is of at least 1.2 
kg finished weight, is at least 1370 mm wide, and has a finishe d vinyl coating of 1.06 broken 
twill when tested using the following test methods (CFFA-1A; CF FA-3; CFFA-6A; CFFA-10; 
CFFA-16C; and CFFA-17) according to Chemical Fabrics and Film A ssociations Standard 
Note: Material of equivalent or better quality may be used. 
5.2.3.2  In the case of Type B, C, and D buses, the driver’s seat shall  have vertical and before 
and after adjustment of at least 100 mm. 
 
 
 
(1) Follow the standard 49 CFR 571.222 until the Saudi standard is adopted SASO S TANDAR D SASO/FDS 31827/2020
12 
 5.2.3.3  In the case of Type B, C, and D buses, the driver’s seat shall  be mounted to allow it to 
adjusted in such a way that it can be positioned from 280 to 38 1 mm from the rearward most 
point of the steering wheel under the following conditions: 
a) With the seat centered in its vertical travel; 
b) With the seat back, if adjustable, in a vertical position; and  
c) With the steering wheel centered in its travel for tilt and /o r telescope positions, as 
applicable. 
 
5.5.4 Supervising seats  
5.5.4.1 The school bus shall be equipped with at least one seat for sup ervisor when the 
number of seats is 20 passengers or less. 
5.5.4.2  The school bus shall be equipped with at least two seats for s upervisor when the 
number of seats is more than 20 passengers. 
5.5.4.3  The supervisor's seat shall be located in the direction of the  students on the aisle of the 
bus and close to the passenger door.   
5.5.4.4  When there is more than one of the supervisory seats, there sh all be at least one of the 
supervisory seats close to the emergency door.  
5.5.4.5  The Supervision seats shall be provided with a three-point saf ety belt.  
5.5.4.6  Supervising seats must be marked.  
5.5.4.7  Supervision seats may be foldable.  
 
5.6 Alternator 
5.6.1  All Type A and B buses with a GVWR of 6800 kg or less shall ha ve a minimum 130 A 
alternator. 
Buses equipped with an electrically powered wheelchair lift and /or air conditioning shall be 
equipped with an alternator of the highest rated capacity avail able from the chassis original 
equipment manufacturer. 
5.6.2  All buses over 6800 kg GVWR shall be equipped with a heavy-dut y truck or bus type 
alternator having a minimum output rating of 200 A or higher, and the alternator should pro duce 
a minimum current output of 50% of the rating at engine idle sp eed. 
5.6.3  All buses over 6800 kg GVWR equipped with an electrically powe red wheelchair lift 
and/or air conditioning shall have a minimum alternator output of 240 A and may be equipped 
with a device that advances the engine idle speed when the volt age drops to, or below, a pre- 
set level. 
5.6.4  A belt-driven alternator shall be capable of handling the rate d capacity of the alternator 
with no detrimental effect on any other driven components. 5.6.5  A direct/gear-drive alternator is permissible in lieu of a bel t-driven alternator. 
 
5.7 Batteries 
5.7.1  The batteries of school bus shall meet the engine starting and  other electrical load 
requirements. 
5.7.2  The manufacturer shall securely attach the battery on a slide- out or swingout tray in a 
closed, vented compartment outside the passenger compartment at  the body skirt or chassis 
frame so that the battery is accessible for convenient servicin g from the outside or cut off the 
electrical supply in case of an impact. SASO S TANDAR D SASO/FDS 31827/2020
13 
 5.7.3  When in the stored position, the tray shall be retained by a s ecuring mechanism capable 
of holding the tray in position when subjected to a 5g load fro m any direction 
5.7.4  The battery compartment door or cover, if separate from the tr ay, shall be hinged at the 
front or top. 
5.7.5  The door may be an integral part of the battery slide tray. 
5.7.6  The door or cover shall fit tightly to the body, and not prese nt sharp edges or snagging 
points. 
5.7.7  Any chassis frame-mounted batteries shall be relocated to a ba ttery compartment on Type 
A buses. 
5.7.8  In all cases the battery cable provided with the chassis shall  have sufficient length to allow 
some slack, and shall be of sufficient gauge to carry the requi red amperage. 
5.7.9  All school buses provided with 6 V and 12 V lead-acid batterie s shall meet the technical 
requirements  according  to  Saudi  Standard  SASO  GSO  34  wh en  tested  in  accordance 
SASO GSO 35. 
 
5.8 Brakes 
5.8.1 General 
5.8.1.1  Each school bus shall be equipped with service brake system ad equate to control the 
movement of, and to halt it safely, speedily and effectively wh atever its speed and load, on any 
up or down gradient. 
5.8.1.2  The braking system provided on the school bus shall be suitabl e for it and ensure safe 
braking performance under normal and emergency conditions. 
5.8.1.3  The effectiveness of the brake system shall be checked by meas uring the stopping 
distance. 
5.8.1.4  Any material affecting public health shall not be used in the brake system directly or 
after its interaction with other elements such as asbestos and cadmium. 
5.8.1.5  The control of the service brake device shall be independent o f the control of the parking 
braking device. 5.8.1.6  The driver shall control the service brake pedal by his right foot. 
5.8.1.7  All buses shall have either a parking pawl in the transmission  or a park brake interlock 
that requires the service brake to be applied to allow release of the parking brake. 
5.8.1.8  Each brake drum or rotor shall be permanently marked with a le gible cast or stamped 
legend that clearly indicates the maximum safe inside diameter (in the case of the drum) or 
minimum safe thickness (in the case of the rotor) beyond which it should not be used. 
5.8.1.9  The brake lines, 
booster-assist lines, and control cables shall be protected from excessive 
heat, vibration and corrosion and installed so that they are pr otected from chafing. 
5.8.1.10 All brake systems of school buses shall be designed to permit v isual inspection of brake 
lining wear without removal of any chassis component other than  inspection covers and dust 
covers. 
5.8.1.11  All school buses shall be provided with Anti-lock braking syst em (ABS) according to 
Standard(2). 
 
 
 
(2) Follow the standard 49 CFR 571.105 & 49 CFR 571.121 or ECE 13 u ntil the Saudi standard is adopted SASO S TANDAR D SASO/FDS 31827/2020
14 
 5.8.1.12  The parking brake system for either air or hydraulic service b rake systems may be of 
a power-assisted design. 
5.8.1.13  The power parking brake actuator shall be a device located on the instrument panel 
within reach of a driver. 5.8.1.14  The power-operated parking brake system may be interlocked to the engine key switch. 
Once the parking brake has been set and the ignition switch tur ned to the off” position, the 
parking brake cannot be released until the key switch is turned  back to the “on” position. 
5.8.2 
Hydraulic and electric brake syste ms 
5.8.2.1  All school buses equipped with a hydraulic and electric servic e brake systems and 
parking brake systems shall meet the technical requirements acc ording to Standard(3). 
5.8.3 Air brake syste ms 
5.8.3.1  All school buses equipped with air brake systems shall meet th e technical requirements 
according to Standard(4). 
5.8.3.2  The air pressure supply system shall include a desiccant-type air dryer installed 
according to the manufacturer’s recommendations and the air pre ssure storage tank system may 
incorporate an automatic drain valve. 5.8.3.3  The chassis manufacturer shall provide an accessory outlet for  air-operated systems 
installed by the body manufacturer and this outlet shall includ e a pressure protection valve to 
prevent loss of air pressure in the service brake reservoir 
5.8.3.4  An air pressure gauge shall be provided in the instrument pane l. 
5.8.3.5  Air brake systems shall include a system for anti-compounding of the service brakes 
and parking brakes. 
5.8.3.6  Air brakes shall have both a visible and audible warning devic e whenever the air 
pressure falls below the level. 
 
 
5.9 Exhaust system 
5.9.1 General 
5.9.1.1 The exhaust gases shall not be allowed into the passenger compa rtment, which affects 
passenger health. 5.9.1.2 The exhaust pipe, muffler, and tailpipe shall be located outsid e the passengers' 
compartment and attached to the chassis so any other chassis co mponent is not damaged, except 
that the last tailpipe hanger may be attached to the body. 
5.9.1.3  Adequate clearance or heat protection shall be provided betwee n the exhaust system and 
the fuel tanks, fuel lines, flexible brake lines and hose, or o ther flammable material to prevent 
ignition and/or heat deterioration. 
5.9.2 Type A 
buses 
5.9.2.1  The engine exhaust system shall meet the original equipment ma nufacturer’s 
specifications. 
5.9.2.2  In no case shall any portion of exhaust be discharged directly  beneath a wheelchair lift, 
emergency exit door, or a gasoline or diesel fuel fill opening.  
 
 
(3) Follow the standard 49 CFR 571.105 or ECE 13 until the Saudi st andard is adopted . 
(4) Follow the standard 49 CFR 571.121 or ECE 13 until the Saudi st andard is adopted SASO S TANDAR D SASO/FDS 31827/2020
15 
  
5.9.3 Type B, C, and D buses 
In addition to being in accordance with Clause 5.9.1, the exhau st systems shall comply with the 
following Clause: 
5.9.3.1  The tailpipe shall be constructed of a corrosion resistant tub ing material at least equal 
in strength and durability to 16-gauge steel tubing of equal di ameter. 
5.9.3.2  The engine exhaust system shall meet the original equipment ma nufacturer’s 
specifications. 
5.9.3.3  The exhaust system tailpipe shall terminate flush with or no m ore than 50 mm beyond 
the rear bumper. 
5.9.3.4  In no case shall any exhaust be discharged directly beneath a wheelchair lift, emergency 
exit door, or a gasoline or diesel fuel fill opening. 
 
5.10 Sound signaling device 
5.10.1  All school buses shall be equipped with a sound signaling devi ce (horn) capable of 
emitting a continuous, uniform sound and its acoustic spectrum shall not vary substantially 
during its operation that meet the technical requirements of Sa udi Standard SASO GSO 99. 
5.10.2 All school buses shall be equipped with an audible alarm  that will operate automatically 
when the bus is traveling to the back, making a sound heard suf ficiently to alarm pedestrians 
and other vehicles in the back, and the sound level shall be fr om 87 to 120 dBA. 
 
5.11 Front bum per 
5.11.1  All school buses shall be provided a front bumper. 
5.11.2  The bumper shall extend beyond the forward-most part of the bo dy, grille, hood and 
fenders and shall extend to the outer edges of the fenders at t he bumper’s top line to ensure 
maximum fender and body protection. 5.11.3 The front bumper shall be strong enough to push another vehicle  of equally rated GVW 
on level ground without causing permanent distortion to the bum per, chassis, or body. 
5.11.4  The front bumper on buses of Type A-2 (with GVWR greater than 6600 kg), Type B, 
Type C, and Type D shall be equivalent in strength and durabili ty to pressed steel channel at 
least 5 mm thick and not less than 200 mm wide (high). 5.11.5  If the front bumper is used for lifting, the contact points sh all be under the bumper 
attachments to the frame rail brackets unless the manufacturer specifies different lifting points 
in the owner’s manual. 
5.11.6  The front bumper shall be of sufficient strength to permit bei ng pushed by another 
vehicle on a smooth surface with a 5-degree, (8.7 percent) grad e, without permanent distortion. 
5.11.7  The bumper shall be designed or reinforced so that it will not  deform when the bus is 
lifted by a chain that is passed under the bumper (or through t he bumper if holes are provided 
for this purpose) and attach ed to both tow hooks/eyes. 
 
5.12 Rear bum per 
5.12.1  All school buses shall be provided a rear bumper and shall be attached directly to the 
chassis frame in a manner that prevents hitching or riding ther eon, and with provisions for easy 
removal. SASO S TANDAR D SASO/FDS 31827/2020
16 
 5.12.2  The rear bumper shall be of sufficient strength to permit the bus to be pushed at rated 
GVW on level ground by another vehicle without causing permanen t distortion to the bus. 
5.12.3  The rear bumper shall be constructed and attached to the bus i n a manner that develops 
the full strength of the bumper section upon rear or side impac t. 
5.12.4  The rear bumper shall extend beyond the rear-most part of the body surface at least 25 
mm, measured at the floor line. 
5.12.5   In  addition  to  meeting  the  requirements  specified  in  Clause  5.12.1  to  5.12.4, 
the rear bumper on Type A2, B, C, and D buses shall meet the fo llowing requirements: 
a) it shall be of pressed steel channel or an equivalent material  at least 5 mm thick and 240 mm 
high; 
b) it shall be wrapped around the back corners of the bus; and 
c) it shall extend forward at least 300 mm, measured from the rea r-most point of the body at the 
floor line, and shall be mounted flush with the sides of the bo dy or protected with an end panel. 
5.12.6  The rear bumper on Type A-1 buses shall be a minimum of 200 mm  wide (high). 
5.12.7  The bottom of the rear bumper shall not be more than 760 mm ab ove ground level. 
 
5.13 Shock absorbers 
The school bus shall be equipped with front and rear double-act ing shock absorbers that 
compatible with the manufacturer GAWR. 
 
5.14 Drive shaft  
The drive shaft shall be prot ected by a metal guard around the circumference of the drive shaft 
to reduce the possibility of its whipping through the floor or floor or dropping to the ground if 
broken. 
 
5.15 Engine 
5.15.1  The engine shall be suitable for the type of fuel used domesti cally, either unleaded 
gasoline or diesel oil specially with respect to Sulphur conten ts and the deterioration effect on 
the accessories equipped with exhaust emission controls. 
5.15.2  The engine and its accessories shall be suitable for use in in  dusty weather conditions 
and high ambient temperatures especially as concerns the radiat or (type and size), air filter, 
engine block cooling system, thermostat and battery. 
5.15.3  The on-board diagnostic (OBD) system (Stage One) shall be suit able to enable it to 
identify the types of deterioration or malfunction over the ent ire life of the bus. 
5.15.4  The GVWR of any school bus shall not exceed 84.0 kg per certif ied net published 
horsepower of the engine at rated speed. 
5.15.5   Method of engine speed testing to evaluate their performance shall be according to Saudi 
Standard SASO GSO ISO 1585.  
5.16 Steering Syste m 
5.16.1  The steering system shall be such as to be easily and securely  handled by the driver in 
his normal driving position. 
5.16.2  The steering wheel shall be on the left side. 
5.16.3  Changes shall not be made to the steering apparatus unless app roved by the chassis 
manufacturer. SASO S TANDAR D SASO/FDS 31827/2020
17 
 5.16.4  There shall be a clearance of at least 50 mm between the steer ing wheel rim and the 
cowl, instrument panel, windshield, or any other surface. 
5.16.5  For buses equipped with adjustable steering wheels, a clearanc e of less than 50 mm shall 
be permitted during driver entry and egress from the seat; howe ver, the steering wheel shall be 
designed to permit a minimum clearance of 50 mm during operatio n of the bus. 
5.16.6  The steering system shall be designed to provide a means for l ubrication of all wear 
points that are not permanently lubricated. 
5.16.7  When the steering control system (for school buses with a gros s vehicle weight (GVW) 
of 4500 or less) is impacted by a body block at a relative velo city of 24 km/h., the impact 
force on the chest of the body block transmitted to the steerin g control system shall not exceed 
11,120 N according to SASO/FDS 31841 “Road vehicles - Impact pr otection for the driver 
from the steering control system” (FMVSS 571.203). 
5.16.8  When a school bus with a gross vehicle weight rating (GVWR) of  4,500 kg or less 
is tested according to  SASO GSO 36  at 48 km/h perpendicular i mpact into a fixed collision 
barrier, the upper end of the steering column and shaft in the vehicle shall not be displaced more 
than 127 mm in a horizontal rearward direction parallel to the longitudinal axis of the vehicle 
as shown in Saudi Standard SASO GSO 40. (FMVSS 571.204) 
 
5.17 Tyres and wheels 
5.17.1  All tyre on a school bus, including the spare if provided, sha ll be of the same size. 
5.17.2 The school bus shall be equipped with a spare tyre and suitably  mounted in an accessible 
location outside the passenger compartment. 
5.17.3  All Tyre shall meet the technical requirements according to Sa udi Standard SASO GSO 
647 when tested in accordance SASO GSO 646. 5.17.4  School buses tyres shall be provided with speed symbol (M) (13 0 km/h) and higher rating 
tyres. 
5.17.5  All school busses shall be provided with a Tyre Pressure Monit oring System (TPMS) 
which informs the driver when a tyre is below the vehicle manuf acturers recommended running 
pressure except those school busses with dual rear wheels on an  axle, and shall comply with the 
technical requirements of Standard
(5). 
5.17.6 Dual rear wheels shall be pr ovided on Type A2, B, C, and  D buses. 
5.17.7  All wheels and rims shall meet technical requirements in accor dance with Saudi Standard 
SASO GSO ISO 3894, SASO GSO IS O 3911 and SASO GSO ISO 4209-2. 
5.18 Turning radius  
5.18.1  Chassis with a wheelbase of 6700 mm or less shall have a left-  and right-turning radius 
of not more than 13.0 m curb-to-curb measurement. 
5.18.2  Chassis with a wheelbase greater than 6700 mm shall have a lef t- and right-turning radius 
of not more than 13.5 m curb-to-curb measurement.   
 
(5) Follow the standard 49 CFR 571.138 or ECE 141 until the Saudi s tandard is adopted . SASO S TANDAR D SASO/FDS 31827/2020
18 
 5.19 Windshield defrosting  and defogging syste ms 
5.19.1  The Defrosting and defogging equipment shall direct a sufficie nt flow of heated air onto 
the windshield, the window to the left of the driver and the gl ass in the viewing area directly to 
the right of the driver to eliminate frost and fog. 
5.19.2  The defroster and defogging system shall be capable of furnish ing heated, outside 
ambient air, except that the part of the system furnishing addi tional air to the windshield, 
entrance door and stepwell may be the re-circulating air type. 
5.19.3 Auxiliary fans are not considered defrosting or defogging syste ms. 
5.19.4  Portable heaters shall not be used. 
5.19.5  The defroster system shall meet the performance requirements o f Standard 
SASO/FDS 31837 " Road vehicles - W indshield defrosting and defo gging systems" 
 
5.20 Windshield wiping and washing syste m 
5.20.1  Each school bus shall be provided with a power-driven windshie ld wiping system that 
meet the technical requirements of Standard SASO/FDS 31839 "Roa d vehicles - 
Windshield wiping and washing systems".(FMVSS 571.104) 
5.20.2  Each windshield wiping system shall have at least two frequenc ies or speeds. 
5.20.3  One frequency or speed shall be at least 45 cycles per minute regardless of engine load 
and engine speed. 
5.20.4  The lower frequency or speed shall be at least 20 cycles per m inute regardless of engine 
speed and engine load. 
5.20.5  The highest and one lower frequency or speed shall differ by a t least 15 cycles per 
minute. 5.20.6  Each school bus shall be provided with a windshield washing sy stem that meets the 
technical requirements of Standard SASO/FDS 31839 "Road vehicle s - Windshield wiping 
and washing systems".(FMVSS 571.104) 
 
5.21 Front fenders 
5.21.1 The width of the front fenders measured from their outer edges along the fender line 
shall exceed the total spread of the front tires when the front  wheels are in the straight-ahead 
position. 5.21.2 Front fenders shall be properly braced and shall not require at tachment to any part of the 
body. 
 
5.22 Service door 
5.22.1 General 
5.22.1.1  The service door shall be on the right side of the bus, within  direct view of the driver. 
5.22.1.2  The service door shall be operate d electronically, and shall b e provided with a manual 
means to facilitate its opening from the inside during an emerg ency. 
5.22.1.3  The service door shall be designed so that the driver in his s eat can control the opening 
or closing. 5.22.1.4 The service door shall be designed so as to afford easy release  but prevent accidental 
opening. SASO S TANDAR D SASO/FDS 31827/2020
19 
 5.22.1.5  The service door shall be of the split or bifold type, and sha ll open outward. 
5.22.1.6  The vertical closing edges of the split or bifold type service  door shall be equipped 
with flexible material to minimize the possibility of injury. 
5.22.1.7  Service door openings shall be padded at the top interior edge , and padding shall be at 
least 75 mm wide, at least 25 mm thick, and extend the full wid th of the door opening. 
5.22.1.8  If the service door is equipped with a security lock, the hand le shall be incapable of 
being moved from the locked to unlocked position (or vice versa ) without use of a key. 
5.22.1.9  Manual door controls shall not require more than 9 kg of force  to operate at any point 
throughout the range of operation, as tested on a 10% grade, bo th uphill and downhill. 
5.22.1.10  All service door glass shall be approved safety glass. 
5.22.1.11 The bottom of each lower glass panel shall be not more than 254  mm from the top 
surface of the bottom step. 
5.22.1.12  The top of each upper glass panel when viewed from the interio r shall be not more 
than 76 mm below the interior door control cover or header pad.  
5.22.1.13  If Type A bus with a separate entrance door for the driver is equipped with a security 
lock on the service door, the bus  shall be equipped with a devi ce that prevents the engine from 
starting when the service door lock is engaged. 
Note: When a hand lever is used, no parts shall come together in a manner that could shear or crush fingers. 
 
5.22.2 Service door emergency release 
5.22.2.1  The service door shall be equipped with manual emergency relea se mechanism that 
can be operated from the exterior of the bus. 
5.22.2.2  Power-operated doors shall be equipped with an emergency overr ide operated from 
the interior in case power failure. 5.22.2.3 If the exterior emergency release mechanism is equipped with a lock, the bus shall be 
equipped with a device that prevents the engine from starting w hen the lock is enabled. 
5.22.2.4  The words “SERVICE  DOOR 
EMERGENCY RELEASE”  in Arabic and English, 
in black lettering, shall be displayed adjacent to the manual e mergency release device required 
by Clause 5.22.2.1 and 5.22.2.2. 
The lettering shall comply with the following requirements: 
a) it shall be at least 25 mm high; 
b) the stroke width of the lettering shall be at least 4 mm; or 1 /6 of the height of letters; and 
c) exterior lettering shall have a yellow background. 
5.22.3 Type A buses 
5.22.3.1  In addition to meeting the requirements of Clauses 5.22.1 and 5.22.2, the entrance shall 
have a minimum horizontal opening width of not less than 584 mm  and a minimum vertical 
opening of 1727 mm. 
5.22.4 Type B, C, and D buses 
5.22.4.1  In addition to meeting the requirements of Clauses 5.22.1 an 5 .22.2, the service doors 
shall meet the following requirements: 
a) The service door shall have a minimum horizontal opening of 61 0 mm and a minimum 
vertical opening of 1727 mm. SASO S TANDAR D SASO/FDS 31827/2020
20 
 b) The upper and lower door panels shall contain double hermetica lly sealed safety glass. 
c) The bottom of the lower glass panels shall be located not more  than 900 mm from the ground 
when the bus is unloaded. 
d) The top of the upper glass panel shall be located not more tha n 152 mm from the top of the 
door. 
Note: An equivalent product may be used if it meets the performance characteristics of hermetically sealed safety 
glass. 
 
5.22.5 Handrail 
5.22.5.1  A handrail shall be provided on the left and right sides of th e service door entrance and 
meet the following requirements: 
a) it shall be securely mounted on the inside of the body and sha ll extend down to a location 
not more than 813 mm above the ground; 
b) its top shall be a minimum of 711 mm above the level of the pa ssenger compartment floor; 
c) It shall be made from 25 ± 7 mm outside diameter circular cros s-section material and be 
constructed from corrosion resistant material; and 
d) It shall be designed to prevent entanglement. 
5.22.5.2  If a second handrail is installed on the dashboard side of the  service entrance, 
the following requirements shall be met: 
a) It shall meet the requirements of Clause 5.22.5.1, except that  the height of the handrail may 
be reduced to provide clearance at the door control; and 
b) The horizontal opening of the service entrance shall meet the minimum width 
requirements of Clauses 5.22.3 and 5.22.4.1(a). SASO S TANDAR D SASO/FDS 31827/2020
20 
 5.23 Emergency exits 
5.23.1 General 
5.23.1.1  All school buses shall be equipped with emergency exits. 
5.23.1.2  Any  installed  emergency  exit  shall  comply  with  the  des ign  and  performance 
requirements according to Standard(6). 
5.23.1.3  Each emergency door, roof hatch, or window above the rear diva n seat shall be 
designed to be opened from the inside and outside of the bus. 5.23.1.4  Provision for opening from the outside shall consist of a non- detachable device 
designed to prevent hitching but to permit opening when necessa ry. 
5.23.1.5  Each emergency exits shall be equipped with a device that prev ents operation of the 
bus if the is locked. 
5.23.2 
Emergency door s 
5.23.2.1  The rear emergency door shall be equipped with a device to pre vent it from swinging 
beyond the body side line. 
5.23.2.2  Each emergency exit door shall be equipped with a positive doo r-opening device so 
that: 
a) Bear the hinged weight of the door; 
b) Maintains the door in an open position at a minimum of 90 degr ee from the bus body; and 
c) Provides a means for release or override. 
Note: The positive door-opening device shall meet the requirements of Items a) and b) without the need for action 
beyond opening the door past the 90-minimum degree from the bus body. 
5.23.2.3  No exterior device that can be used as a hitch or handle for r iding shall be installed on 
the door. 
5.23.2.4  The upper portion of each emergency exit door shall be equippe d with safety glazing 
material, having an exposed area of not less than 2580 cm2. 
5.23.2.5  The lower portion of the rear emergency door shall be equipped  with safety glazing 
material having an exposed area of not less than 2260 cm2. 
5.23.2.6  Padding at the top of the door opening shall be at least 75 wi de and at least 25 mm 
thick, and extend the full width of the door opening. 
5.23.2.7  There shall be no steps leading to the emergency door. 
5.23.2.8  There shall be no obstruction higher than 6 mm across the bott om of any emergency 
door opening. 5.23.2.9 Fasteners used within the emergency exit opening shall be free of sharp edges or burrs. 
5.23.2.10  Seats or other fixed objects shall be placed in the bus in suc h a way that when 
measured from the rear emergency exit door, the aisle shall all ow an opening, at minimum: 
a) 608 mm wide × 304 mm deep × 1140 mm high for Type A1 buses; 
b) 608 mm wide × 608 mm deep × 1140 mm high for Type A2, B, C, an d D buses. 
5.23.2.11  Emergency doors shall be equipped with a locking mechanism des igned to as a 
security (Vandal) lock, and the lock shall prevent the operatio n of the bus while lock engaged. 
 
 
(6) Follow the standard 49 CFR 571.217 until the Saudi standard is adopted. SASO S TANDAR D SASO/FDS 31827/2020
21 
 5.23.2.12  All emergency exit doors shall be accessible by a 300 mm minim um aisle. 
5.23.2.13  A flip seat in the unoccupied (up) position shall not obstruct  the 300 mm minimum 
aisle to any side emergency exit door. 
5.23.3 Roof hatches 
5.23.3.1  At least one roof hatch, centered approximately side-to-side a nd front-to-back of the 
passenger compartment, shall be provided in all school buses. 
5.23.3.2  Where two or more roof hatches are provided, they shall be cen tered side-to-side and 
approximately equally spaced front-to-back in the passenger com partment. 
5.23.3.3  The roof hatch and the surroundings of the roof hatch frame sh all not permit the 
Passenger of a sphere with a diameter of 100 mm when it is pres sed through any opening by 
a force of 22 N, including the weight of the sphere, when teste d in accordance with Annex 
(A). 
5.23.4 Rear windows 
5.23.4.1  If the school bus is equipped with a window emergency exit abo ve the rear divan seat, 
the area between the top of the seat and the lower edge of the window shall be capable of 
supporting a 90 kg mass over any 26 cm2 area. 
5.23.4.2  The rear emergency window shall have a lifting assistance devi ce that will aid in lifting 
and holding the rear emergency window open. 
5.23.5 Side windows 
5.23.5.1 General 
A school bus equipped with emergency exit side windows shall ha ve an even number of such 
windows, evenly divided between the right and left sides of the  bus, and these windows shall 
be approximately equally spaced along both sides of the bus. 
Note: 
1) The location of the emergency exit side windows takes priority over the loc ation of LATCH seats. 
2) prohibit  LATCH seats from being located beside an emergency exit side window. 
5.23.5.2  No side emergency exit window will be located above a stop arm . SASO S TANDAR D SASO/FDS 31827/2020
22 
 5.23.5.3  Type A2, B, C, and D buses 
5.23.5.3.1  Each side of the school bus shall have at least one hinged eme rgency exit side 
window, preferably located mid- bus. 
5.23.5.3.2  For school buses with a capacity of 37 passengers or more, eac h side of the bus shall 
have at least two hinged emergency exit side windows. 
 
5.23.6 Number and types of emergency exits 
The use of the following tables is to determine the required nu mber and types of emergency 
exits, based on the bus seating capacity as following: 
a) Use Table (1) if the bus contains a rear emergency door, or 
b) Use Table (2) if the bus contains a rear pushout emergency win d o w  A N D  a  l e f t  s i d e  
emergency door. 
 
Available 
combinations 
by capacity Manufacturers 
equipped capacity Roof
hatches Side emergency
exit windows 
(left) Side emergency 
exit windows 
(Right) Side emergency
exit door 
(left) 
1 - 45 1  -  45 1 0 0 0 
 
46 - 77 46 - 77 2 1 1 0 
46 - 77 2 0 0 1 
 
78 - 93 78 - 93 2 2 2 0 
78 - 93 2 1 1 1 
 
Table (1) – School buses with rear emergency door 
(All front engine buses)  
 
Available 
combinations 
by capacity Manufacturers 
equipped capacity Roof 
hatches Side emergency 
exit windows 
(Left) Side emergency 
exit windows 
(Right) Side emergency 
exit door 
(Right) 
1 - 45 1  -  45 1 0 0 0 
 
46 - 89 46 - 89 2 1 1 0 
46 - 89 2 0 0 1 
 
90 - 105 90 - 105 2 2 2 0 
90 - 105 2 1 1 1 
 
Table (2) – School buses with rear pushout window and left side emergency door 
(All rear engine buses)  
 
5.24 Floor covering 
5.24.1  The floor covering in the under seat area (including the wheel  housing), the driver’s 
compartment, the toe board area, the aisle, and the entranceway s shall have a minimum overall 
thickness of 3.18 mm. 
Note: For Type A and B buses, the floor covering in the driver’s compartment and toe board area shall meet 
the original equipment manufacturer’s speci fication. 
5.24.2  The floor covering in the under seat area (including the wheel  housing), the driver’s 
compartment, the toe board area, the aisle, and the entranceway s shall have a burn rate of 0. 1 
mm per minute or less calculated using the test methods, proced ures, and formulas specified in 
SASO/FDS 31842 “Road vehicles - Flammability of interior materi als”.  (FMVSS 571.302) SASO S TANDAR D SASO/FDS 31827/2020
23 
 5.24.2  The floor covering in the aisle and entrance areas shall be sl ip resistant and have a 
minimum coefficient of friction of 0.6 when tested in accordanc e with ASTM D2047 or 
0.85 when tested in accordance with SASO GSO ASTM D1894. 
5.24.3  The floor covering shall not crack when subjected to sudden te mperature change. 
5.24.4  The floor covering shall be securely bonded to the floor with a waterproof material 
recommended by the manufacturer of the floor covering material,  exception of the driver’s area. 
5.24.5 All seams shall be heat welded or sealed with a waterproof seal er. 
 
5.25 Insu lation 
5.25.1  The ceiling and walls of the bus shall be insulated with mater ials to deaden sound and 
vibration and reduce heat transfer and shall meet the flammabil ity requirements in Standard 
SASO/FDS 31842 “Road vehicles - Flammability of interior materi als”.  (FMVSS 571.302) 
5.25.2  All insulating materials used for the reduction of heat transf er shall have an “R” value 
of at least 5.5. 
5.25.3 A formed-in-place type of insulation shall be of equivalent per formance. 
 
5.26 Interior 
5.26.1  The interior of the bus shall be free of all unnecessary proje ctions (include luggage racks 
and attendant handrails) to minimize the potential for injury. 
5.26.2  Overhead luggage racks shall be prohibited. 
5.26.3  There shall be an inner lining on the ceiling and walls. 
5.26.4  If the inner lining contains lapped joints, the forward lining  panel shall be lapped by the 
rear lining panel, and exposed edges shall be beaded, hemmed, f langed, or otherwise treated to 
minimize sharp edges. 
5.26.5  A means of securement shall be provided for cleaning equipment  installed in suitable 
position that does not impede passenger safety or driver visibi lity. 
5.26.6  The securement device shall be designed to retain the equipmen t (e.g. a broom or mop). 
5.26.7  A waste receptacle, with a removable insert, shall be securely  installed so as not to create 
a tripping hazard or impede passenger entry or exit, and the lo cation shall be forward of the 
front barrier, maintain the minimum aisle width, and not impede  driver visibility. 
 
5.27 Lamps, reflectors, and signal s 
5.27.1 Turn-signals and stop/tail lamps 
5.27.1.1  Each school bus shall be equipped with rear turn-signal lamps.  
5.27.1.2  The rear turn-signal lamps shall be illuminated in amber color . 
5.27.1.3  The rear turn-signal lamps shall be not less than 178 mm in di ameter or if a shape other 
than round, a minimum 245 cm2 of illuminated area. 
5.27.1.4  Turn-signal lamps shall be connected to the chassis hazard war ning switch so that they 
will flash when needed as a vehicular traffic hazard warning. 5.27.1.5  Turn signal lamps are to be placed as wide apart as practical and their horizontal 
centerline shall be a maximum of 300 mm below the rear window. 
5.27.1.6  Each school bus shall be equipped with amber side-mounted turn  signal lamps. SASO S TANDAR D SASO/FDS 31827/2020
24 
 5.27.1.7  The side turn signal lamp on the left side shall be mounted re arward of the stop signal 
arm and the side turn signal lamp on the right side shall be mo unted rearward of the entrance 
door. 
5.27.1.8  Each school bus shall be equipped with four combination stop/t ail lamps as following: 
a) Two combination lamps with a minimum diameter of 178 mm in dia meter or if a shape other 
than round, a minimum 245 cm2 of illuminated area shall be mounted on the rear of the bus jus t 
inside the turn signal lamps. 
b) Two combination lamps with a minimum diameter of 100 mm, or if  a shape other than round, 
a minimum of 77 cm2 of illuminated area, shall be placed on the rear of the body be tween the 
beltline and the floor line. 
5.27.1.9  The stop/tail lamps shall be illuminated in red color. 
5.27.1.10  The rear license plate lamp may be combined with one lower tai l lamp. 
5.27.1.11 Stop lamps shall be activated by the service brakes and shall e mit a steady light when 
illuminated. 
5.27.1.12  The two stop lamps shall be installed at the same elevation as  the turn signal on the 
rear of the bus. 
5.27.2 Alternating flashing warning lamps 
5.27.2.1  All school buses shall be equipped with two red at the rear of  the bus and two red 
lamps at the front of the bus. 
5.27.2.2  In addition to the four red lamps described above, four amber lamps shall be installed 
so that one amber lamp is located near each red signal lamp, at  the same level, but closer to the 
vertical centerline of the bus. The system of red and amber signal lamps shall be wired so that  amber lamps are energized 
manually. 
5.27.2.3  The alternating flashing warning lamps shall meet test procedu re and performance 
requirements according to Standard
(7). 
5.27.2.4  The eight alternating flashing lamps shall be installed in acc ordance with Standard(7), 
except that each amber warning lamp shall be located near each red warning lamp, at the same 
level but closer to the vertical centerline of the bus. 
5.27.2.5  The alternating flashing system shall be controlled so that: 
a) The amber alternating flashing lamps are activated by a mome ntary switch that can operated 
only manually by the driver’s hand or foot: 
b) when the amber alternating flashing lamps are activated and th e bus service door is opened, 
i) The amber warning lamps are automatically deactivated; 
ii) The red alternating flashing lamps are automatically deactivat ed; and 
iii) The stop arm and the crossing arm are extended; 
c) when the service door is opened, the red alternating flashing lamps and stop arm do not 
activate if the momentary switch has not first been activated ( sequential mode); and 
d) The red alternating flashing lamps are deactivated, and the st op ar m and safe ty cr ossing 
arm are retracted, when the following: 
i) The service door is closed; or 
ii) The bus starts to move forward. 
(7) Follow the standard SAE J887 until the Saudi standard is adopte d. SASO S TANDAR D SASO/FDS 31827/2020
25 
 5.27.2.6  Unless the bus is equipped with a driver-controlled override s witch that capable of 
deactivating the warning light system at any point during its o peration, a master control switch 
that energizes the system shall be provided and shall be labell ed or color coded. 
5.27.2.7  An amber and red pilot lamp system shall be provided to alert the as to which warning 
lamp system is activated, and shall be located so that the pilo t lamps are readily visible to the 
seated driver. 5.27.2.8  The alternating flashing lamps switch and pilot lamps shall be  located forward of the 
driver, between the left A pillar and approximately the center of the bus. 
5.27.2.9  The area around the lens of each alternately flashing warning lamps, extending outward 
25 mm to 125 mm, shall be black. 
5.27.3 Floor-level side 
maker lamps 
5.27.3.1  The rear side maker lamps shall be located on all Type A2, B, C, and D buses. 
5.27.3.2  The rear side maker lamps shall be located no more than 150 mm  above or below the 
floor line and horizontally no more than 150 mm forward or rear ward of the location of the 
upper side marker lamp. 
5.27.3.3  The rear side marker lamps shall be equipped with a reflective -type red lens. 
 
5.27.4 Interior lamps 
Interior lamps shall be provided to illuminate the aisle and en trance areas adequately. 
 
5.27.5 Exterior lamps 
Tail lamps, side marker lamps, clearance lamps, and identificat ion lamps shall be activated with 
the daytime running lamp (DRL) system. 
Note: All exterior lighting should be LED except head/park/turn combination assemblies. 
 
5.27.6 Strobe lamps 
5.27.6.1  An optional white flashing strobe lamp may be installed on the  roof of a school bus at 
a location not to exceed the body length forward from the rear of the roof edge. 
5.27.6.2  If the bus is equipped with a roof hatch or other roof mounted  equipment falling within 
the above-mentioned measurements, the strobe lamp may be locate d directly behind that 
equipment. 
5.27.6.3  The lamp shall have a single clear lens emitting light 360 deg rees around its vertical 
axis. 
Note: When utilizing LED strobe lamps, minimum speci fications  shall be in compliance with Standard(8) . 
5.27.6.4  Strobe lamp shall have a switch lighted in the ON position or an interior indicator lamp 
that is visible to the driver. 
 
5.27.7 Exit lamps 
The school bus shall be equipped with an exterior lamp will ill uminate the area on the right side 
of the bus at the most forward point on the front bumper to the  centerline of the rear axle, 
and it shall include the following: 
a) Project white light; 
b) Allow operation of the lamp system when the alternating flashi ng warning lamps are 
activated. 
(8) Follow the standard SAE J845 Class 2 requirements until the Sau di standard is adopted. SASO S TANDAR D SASO/FDS 31827/2020
26 
 c) With the service door and windows closed, shall produce a mini mum illumination of 10 lux 
when measured at each point on the grid on a vertical surface a t 0.5 m and 1.0 m above the 
ground; 
d) 10 lux at the vertical outside surface of the bus measured at the outer surface of the bus and 
outward at 1.0 m and 2.0 m and from the most forward point of t he front bumper at intervals of 
every 1-meter proceeding toward the centerline of the rear axle ; 
e) Have a minimum light in a manner that prevents light from shin ing directly into the right-side 
rear-view mirror and crossover mirror; 
f) Turn on when the door is opened; and 
g) Turn off approximately 5 s  after the door has closed. 
 
5.27.8 Backup lamps 
5.27.8.1  The school bus body shall be equipped with two white rear back up lamps that are at 
least 100 mm in diameter or, if a shape other than round, a min imum of 77 cm2 of illuminated 
area. 
5.27.8.2  If backup lamps are placed on the same horizontal line as the brake lamps and turn 
signal lamps, they shall be to the inside. 
 
5.27.9 Exterior lamps for emergency exits 
5.27.9.1 Type A1, A2, B, C, and D (front engine) buse s 
The backup lamps or landing area lamps shall illuminated when t he rear emergency door is 
unlatched. 
5.27.9.2 Type D (rear engine) buses 
All Type D school buses that are equipped with a rear engine sh all be equipped with a backup 
lamp or a landing area that illuminates when the rear emergency  window is unlatched. 
5.27.9.3 Side emergency door exits 
All school buses that are equipped with a side emergency door s hall be equipped with a landing 
area lamp that illuminates when the side emergency door is open ed. 
5.27.9.4 Continuous power to backup and landing area lamps 
Backup and landing area lamps shall operate with the ignition k ey in any position (i.e., there 
shall be continuous power to the lamp). 
5.27.10  All school buses equipped with a monitor for the front and rea r lamps of the school bus, 
the monitor shall be mounted in full view of the driver. 
If the full circuit current passes through the monitor, each ci rcuit shall be protected against any 
short circuit or intermittent shorts by a fuse circuit breaker,  or electronic protection device. 
 
5.28 Rearview 
5.28.1 General 
5.28.1.1  All school bus shall be equipped with an indirect vision devic e to observe the traffic 
area adjacent to the vehicle which cannot be observed by direct  vision. 
5.28.1.2  Indirect vision devices can be conventional mirrors, camera-mo nitors or other devices 
able to present information about the indirect field of vision to the driver. SASO S TANDAR D SASO/FDS 31827/2020
27 
 5.28.2 Mirrors 
5.28.2.1  Each school bus shall be equipped with one internal rear-view mirror and two external 
rear-view mirrors. 
5.28.2.2  All mirrors shall be firmly fixed so that they do not move too  much leading to a change 
in the field of view and thus cause a misinterpretation of the driver to realize what he observes 
when the bus is traveling at high speed. 5.28.2.3  All mirrors shall be shall be adjustable type and mounted in a  position to allow the 
driver in his seat to have a cl ear view of the traffic of other  vehicles on both sides. 
5.28.2.4  All mirrors shall be shall be of unit magnification, if the mi rror is a flat mirror; 
5.28.2.5  All mirrors shall be free of sharp points or edges that could injure an occupant of the 
bus or a pedestrian. 
5.28.2.6  All mirrors shall be installed at a location where the blind s pot created by the mirror is 
minimized. 
 
5.28.3 Exterior rear-view mirrors 
5.28.3.1  Each school bus shall have two outside rear-view mirror system s, called System A and 
System B, and shall comply with Standard(9). 
5.28.3.2  System A mirrors shall be remote controlled along the horizont al and vertical axis, and 
the remote-control actuator shall be located within reach of th e seated driver position. 
 
5.28.4 Interior rear-view mirrors 
5.28.4.1 General 
a) Interior rear-view mirrors shall have rounded corners and padd ed edges; 
b) Interior rear-view mirrors shall be designed to reduce danger of injury upon impact; 
c) Interior rear-view mirrors shall be made of safety glass; and 
d) Interior rear-view mirrors shall afford the driver a view of t he bus interior. 
5.28.4.2 Type A1 and A2 buse s 
In addition to meeting the requirements of Clause 5.28.4.1, the  interior rear-view mirrors shall 
be at least 150 mm high and 400 mm wide. 
5.28.4.3 Type B, C, and D buses 
In addition to meeting the requirements of Clause 5.28.4.1, the  interior rear-view mirrors shall 
be at least 150 mm high and 760 mm wide. 
5.28.5 Rear-view camera 
Each school bus shall be equipped with a rear-view camera that helps the driver to see clearly 
to avoid the risk of accidents while the bus is traveling backw ard, and it is in accordance with 
Saudi Standard SASO GSO ECE 46. 
 
5.29 Stabi lity 
5.29.1  Any school bus shall not overt urn when tilting it is unladen a nd laden state to the left or 
right side at an angle of (35º) or the stability of the bus ove rturn is the point at which the 
overturning occurs and should be limited to lateral acceleratio n. 
5.29.2  All school buses shall be provided with an Electronic Stabilit y Control (ESC).  
 
(9) Follow the standard 49 CFR 571.111 until the Saudi standard is adopted. SASO S TANDAR D SASO/FDS 31827/2020
28 
 5.30 Cooling syste m 
5.30.1  Each school bus shall be equipped with a cooling system suitab le for the climate of the 
Kingdom of Saudi Arabia to keep the engine at the most efficien t operating temperature at all 
engine speeds and under all driving conditions. 
5.30.2  Cooling system in which the liquid is used shall be provided w ith a tool (thermostat) that 
reduces the ineffective or cold operating time of the engine. 
5.30.3  The radiator and cooling fans shall be large enough to reduce the operating temperature 
of the engine to be below the maximum allowable. 
5.30.4  All school buses equipped with a radiator which was use water as a cooling medium 
shall meet the technical requirements according to Saudi Standa rd SASO GSO 136 when tested 
in accordance SASO GSO 135. 
 
5.31 Safety Belts 
5.31.1 Seat belt for driver 
5.31.1.1  The driver shall be provided with a three-point safety belt an d shall meet the technical 
requirements  according  to  Saudi  Standard  SASO  GSO  97  wh en  tested  in  accordance 
SASO GSO 96. 
5.31.1.2  The safety belt shall be designed to allow only one person to use it at one time. 
5.31.1.3  The safety assembly belt does not cause any injury to its user  when the collision occurs. 
5.31.1.4  On buses where the driver’s seat and upper anchorage for the s houlder belt are both 
attached to the body structure, a driver’s seat with an integra ted lap/shoulder belt may be 
substituted. 5.31.1.5  On buses where the driver’s seat and upper anchorage for the s houlder belt are 
separately attached to both body and chassis structures (i.e., one attached to the chassis and the 
other attached to the body), a driver’s seat with an integrated  lap/shoulder belt should be used. 
5.31.1.6  The lap/shoulder belt shall be designed to allow for easy adju stment in order to fit 
properly and to effectively protect drivers varying in size. 
5.31.1.7  Each school bus shall be equipped with a durable webbing cutte r having a full width 
handgrip and a protected, replaceable or non-corrodible blade. 5.31.1.8  The required webbing cutter shall be mounted in a location acc essible to the seated 
driver in an easily detachable manner. 
 
5.32 Steps 
5.32.1 Type B, C, and D buses 
In addition to meeting the requirements of Clause 5.2.4, the st ep shall meet the following 
requirements: 
5.32.1.1 Steps shall not protrude beyond side body line. 
5.32.1.2  The floor line platform area and all steps shall comply with t he following requirements: 
a) They shall be covered with, at a minimum overall thickness of 5 mm elastomer treads backed 
with metal or with an additional 5 mm elastomer. 
The treads shall have at least 38 mm white or yellow nosing, or  shall have a 75 mm white 
elastomer edge, backed with metal or with an additional 5 mm of  elastomer, at the floor line 
platform. SASO S TANDAR D SASO/FDS 31827/2020
29 
 b) The backing of the tread shall be, at a minimum, 24 gauge cold -rolled steel or a 5 mm durable 
backing and shall be permanently bonded to the textured raised elastomer. 
c) The design of the surface shall be grooved in such a way that grooved run at 90 angles to the 
long dimension of the step tread or shall be pebbled, with a mi nimum pebble height of 3.2 mm. 
d) The 5 mm textured step tread shall have 38 mm white or yellow nosing as an integral piece 
without a joint. 
e) The elastomer portion of the tread shall have the following ch aracteristics: 
i) abrasion resistance: special compounding for abrasion resistance shall ensure that t he step 
tread material weight loss does not exceed 0.4% when tested in accordance with ASTM D4060 
(CS-17 Wheel, 1000-gram, 1000 cycle). ii) 
weathering resistance: step treads shall not break, crack, or check after ozone expos ure of 
(7 days at 50 pphm at 40 degrees C) and weather meter exposure in accordance with ASTM 
D750; and 
iii) flame resistance: step treads shall have a burn rate of 0.01 mm per minute or les s calculated 
using the test methods, procedures, and formulas specified in S ASO/FDS 31842 “Road 
vehicles - Flammability of interior materials”. (FMVSS 571.302)  
5.32.1.3  The material shall be applied not only to the interior surface s of the service door step 
treads but also to the exterior, if not covered by undercoating . 
5.32.1.4  The stepwell shall be illuminated by at least one lamp providi ng white light, actuated 
automatically by the opening of the door. 
 
5.33 Stirrup (Type C and D buse s) 
In addition to meeting the requirements of Clauses 5.2.4 and 5. 32.1, steps shall also meet the 
following requirements: 
5.33.1  There shall be one folding stirrup step and a suitable located  handle to permit easy 
accessibility for cleaning the windshield and lamps. 
In the case Type D buses, steps in or on the front bumper may b e used in lieu of stirrup steps. 
5.33.2  The design of the stirrup step s hall not allow any article to become entangled in the step 
when passengers are entering or exiting the bus. 
 
5.34 Stop signal arm  
5.34.1  Each school bus shall be equipped with a stop signal arm as de picted in Figure (1). 
5.34.2  The stop signal arm shall be installed on the left side of the  bus. 
5.34.3  The stop signal arm shall be automatically extended with the p assenger door open. 
5.34.4  Stop signal arm assemblies shall meet the technical requiremen ts and test procedures 
according to SASO/FDS 31830 “School buses - Pedestrian safety d evices”.  (FMVSS 571.131) SASO S TANDAR D SASO/FDS 31827/2020
30 
  
 
 
Figure (1) - characteristic of stop signal device  
 
5.35 Crossing arm  
5.35.1  School buses shall be equipped with a pedestrian-student safet y crossing arm located at 
right front corner of the chassis (the front bumper), and when opened, this arm shall extend in 
a line parallel to the body side and aligned with the right fro nt wheel. 
5.35.2  The pedestrian-student safety-crossing arm shall automatically  open to its fully extended 
position whenever the school bus stop arm is activated, and the  crossing arm shall return to its 
park position when the stop arm is deactivated. 
5.35.3  The crossing arm shall extend at least 1780 mm (measured from the assembly pivot 
point) when in the extended position, the crossing arm shall no t extend past the end of the 
bumper when in the stowed position. 5.35.4 All components of the crossing control arm and all connections shall be weatherproofed. 
5.35.5 The crossing control arm shall incorporate system connectors (e lectrical or air) at the 
gate and shall be easily removable to allow for towing of the b us. 
5.35.6  The crossing control arm shall be constructed of non-corrodibl e or nonferrous material 
or shall be treated in accordance with the body sheet metal spe cification. 
5.35.7  There shall be no sharp edges or projections that could cause injury or be a hazard to 
students and the end of the arm shall be rounded. 
5.35.8  An automatic recycling interrupt switch may be installed for t emporarily disabling the 
crossing control arm. 5.35.9 The assembly shall include a device attached to the bumper near  the end of the arm to 
automatically retain the arm while in the stowed position and t hat device shall not interfere with 
normal operations of the crossing control arm. SASO S TANDAR D SASO/FDS 31827/2020
(10 Follow the standard SAE J1959 until the Saudi standard is adopt ed
31 
 5.36 Sun shield 
5.36.1  The school on Type A buses, the sun shield (visor) shall be in stalled by the chassis 
manufacturer. 
5.36.2  The school on Type B, C, and D buses shall be equipped with an  interior adjustable sun 
shield and install in a position convenient for use by the driv er, as following: 
a) The sun shield shall be tinted at 92 to 95% to allow 5 to 8% l ight transparency. 
b) The viewing area shall not be less than 140 × 750 mm and shall  be adequately supported to 
prevent excessive vibration. 
Note: If additional sunshields are installed, they too shall meet the transparency and securement 
requirements given in this Clause. 
 
5.37 Unde rcoating 
5.37.1  The entire underside of the body, including floor sections, cr oss-members, and below- 
floor-line side panels, shall be coated with rust-proofing mate rial meet all performance 
requirements of according to Standard(10) 
5.37.2  The undercoating compound shall be applied with suitable airle ss or conventional spray 
equipment to the undercoating material manufacturer recommended  film thickness and shall 
show no evidence of voids in the cured film. 
5.37.3  The undercoating material shall not cover any exhaust componen ts of the chassis. 
 
5.38 Ventilation 
5.38.1  The school bus shall be equipped with a suitably controlled ve ntilation system of 
sufficient capacity to supply an adequate quantity of air under  operating conditions without the 
windows being opened (except in extremely warm weather). 
5.38.2  Fan(s) shall be placed in a location where they can be adjuste d for maximum 
effectiveness and where they do not obstruct the driver’s visio n to the mirrors or interfere with 
the safe operation of the vehicle. 
a) Fans shall have 152 mm (nominal) diameter. 
b) Fan blades shall be enclosed in a protective cage . 
c) Each fan shall be controlled by a separate switch. 
5.38.3  All school buses shall be equipped with at least one static-ty pe exhaust vent in a low- 
pressure area of the body. 
5.38.4  Roof hatches designed to provide ventilation in all types of e xterior weather conditions 
may be provided. 
5.38.5  Circulation fans that supply additional air to the windshield may be used, and shall be 
located forward of the driver. 
Note: Circulation fans shall not be used in lieu of the defroster system 
 
5.39 Wheel hous ing 
5.39.1  Wheel housing openings shall allow easy tire removal. 
5.39.2  Wheel housing shall be constructed of sheet steel with a minim um thickness of 1.6 mm 
or another material of equivalent strength and shall be attache d to the floor sheets in a manner 
that prevents dust or water from entering the body. SASO S TANDAR D SASO/FDS 31827/2020
(11 Follow the standard SAE J683 until the Saudi standard is adopte d
32 
 5.39.3  Any portion of a raised wheel housing shall not extend into an  emergency door opening 
or into an aisle leading to an emergency door. 
5.39.4  The inside height of wheel housing above the floor line shall not exceed 300 mm. 
5.39.5 Type A2, B, C, and D buses 
In addition to meeting the requirements of Clause 5.39.1 to 5.3 9.4, the wheel housing shall 
provide clearance for chains on dual wheels according to Stanar ad(11). 
 
5.40 Windshield and windows 
5.40.1 General 
5.40.1.1  All school buses shall be provided with laminated safety glass  on windscreens and 
other windows according to Saudi Standard SASO GSO 1677 when te sted in accordance with 
SASO ISO 3537, SASO ISO 3538, SASO ISO 3917 and SASO ISO 13837.  
5.40.1.2  The windshield and all windows safety glass shall be transpare nt and free from any 
distortions that obscure the visibility of the driver. 5.40.1.3  The windshield and all windows safety glass shall not be affec ted by the atmospheric 
conditions, chemicals and heat. 
5.40.1.4  The rear window safety glass shall be provided with suitable a nti fog system. 
5.40.1.5  The side windows for the passenger compartment, except service  or emergency door 
windows, shall be of the vertical sliding split-sash type. 
5.40.1.6  The maximum area of the opening side windows in the body struc ture shall be 
7100 cm
2. 
5.40.1.7  The driver’s window (if installed by the body manufacturer) sh all be made of double- 
paned hermetically sealed safety glass with an insulating air s pace. 
5.40.1.8  The luminous transmittance of the all windows and windshield s hall be not less than 
70%. 
5.40.2  Each side window safety glass shall provide an unobstructed op ening of at least 230 mm 
high but not more than 330 mm high and at least 558 mm wide, ob tained by lowering the 
window. 
Note: One window on each side of the bus may be less than 558 mm wide. 
5.40.3  When a school bus with a gross vehicle weight rating (GVWR) of  4,500 kg or less 
is tested according to  SASO GSO 36 at 48 km/h impacts a fixed collision barrier that is 
perpendicular to the line of travel of the vehicle, the windshi eld mounting of the vehicle shall 
retain not less than the minimum portion of the windshield peri phery 50 %.as shown in Saudi 
Standard SASO GSO 40. (FMVSS 571.212) SASO S TANDAR D SASO/FDS 31827/2020
33 
 5.41 Electrical compone nts 
5.41.1 Wiring (Chassi s) 
5.41.1.1  Materials in all electrical components shall contain no mercur y. 
5.41.1.2  All wiring shall use color and at least one other method for i dentification and the other 
method shall be either a number code or name code. 
5.41.1.3  Incomplete school bus 
a) The chassis manufacturer of an incomplete vehicle shall instal l a readily accessible terminal 
strip or connector on the body side of the cowl or in an access ible location in the engine 
compartment of vehicles designed without a cowl . 
b) The strip or connector shall contain the following terminals f or the body connections: 
1) Main 100-amp body circuit; 
2) Tail lamps; 
3) Right turn signal; 
4) Left turn signal; 
5) Stop lamps; 
6) Back-up lamps; and 
7) Instrument panel lamps (controlled by dimmer switch). 
5.41.1.4  An appropriate identifying diagram (color plus a name or numbe r code) for all chassis 
electrical circuits shall be provided to the body manufacturer for distribution to the end user. 
5.41.1.5  Wiring for the headlamp system must be separate from the elect ronic controlled body 
solenoid/module. 
 
5.41.2 Wiring (Body) 
5.41.2.1  All wiring shall conform to current applicable SAE recommended  practices. 
5.41.2.2  All wiring shall have an amperage capacity exceeding the desig n load by at least 25%. 
5.41.2.3  A body wiring diagram, sized to be easily read, shall be furni shed with each bus body 
or affixed to an area convenient to the electrical accessory co ntrol panel. 
5.41.2.4  The body power wire shall be attached to a special terminal on  the chassis. 
5.41.2.5 Each wire passing through metal openings shall be protected by a grommet. 
5.41.2.6  Wires not enclosed within the body shall be fastened securely at intervals of not more 
than 455 mm. 
5.41.2.7  Wiring shall be arranged in circuits, as required, with each c ircuit protected by a fuse 
breaker or electronic protection device. 5.41.2.8  A system of color and number-coding shall be used and an appro priate identifying 
diagram shall be provided to the end user, along with the wirin g diagram provided by the chassis 
manufacturer. 
5.41.2.9  Chassis wiring diagrams shall be supplied to the end user in o wner manual (Operating 
Instructions). 5.41.2.10  The following body interconnecting circuits shall be color-cod ed, as noted: SASO S TANDAR D SASO/FDS 31827/2020
34 
  
 
Function Color 
Left-Rear Directional Lamp Yellow  
Right-Rear Directional Lamp D a r k  G r e e n  
Stop Lamps Red 
Back-up Lamps Blue 
Tail Lamps Brown  
Ground White  
Ignition Feed, Primary F eed Black  
 
5.41.2.11  The color of the cables shall correspond to Standard(12). 
5.41.2.12  Wiring shall be arranged in at least six regular circuits, as follows: 
a) Head, tail, stop (brake), clearance and instrument panel lamps ; 
b) Step well lamps shall be actuated when the entrance door is ope n; 
c) Dome lamps; 
d) Ignition and emergency door signal; 
e) Turn signal lamps; and 
f) Alternately flashing signal lamps. 
5.41.2.13  Any of the above combination circuits may be subdivided into a dditional 
independent circuits. 
5.41.2.14  Defrosters shall be wired on an independent circuit: 
5.41.2.15  Whenever possible, all other electrical functions (such as san ders and electric type 
windshield wipers) shall be provided with independent and prope rly protected circuits. 
5.41.2.16  Each body circuit shall be coded by number or letter on a diag ram of circuits and 
shall be attached to the body in a readily accessible location.  
5.41.3  Buses may be equipped with a 12-volt power port in the driver’ s area. 
5.41.4  The entire electrical system of the body shall be designed for  the same voltage as the 
chassis on which the body is mounted. 
 
5.42 Side intrusion 
The school bus body shall be constructed to withstand an intrus ion force equal to the curb 
weight of the vehicle or 88.9 kN, whichever is less. 
Note: Each vehicle shall be capable of meeting this requirement when tested in accordance with the test 
procedu re specified in Annex (B). 
 
5.43 Speedometer and odom eter devises 
5.43.1 Speedometer 
5.43.1.1  Each school bus shall be provided with a speedometer located w ithin the direct field 
of view of the driver in the dashboard so that it can be easily  observed and shall be clearly 
legible both day and night. 
5.43.1.2  The speedometer shall be marked in kilometres per hour (km/h).  
5.43.1.3  The speedometers intended for school buses shall be graduated with 1, 2, 5 or 10 km/h., 
and the numerical speed values shall be indicated at intervals not exceeding 20 km/h. 
 
(12) Follow the standard SAE J1128 until the Saudi standard is adopt ed SASO S TANDAR D SASO/FDS 31827/2020
35 
 5.43.2 Odometer 
5.43.2.1  Each school bus shall be provided with an odometer in a suitab le place in the dashboard 
so that the driver can easily see it. 
5.43.2.2  The odometer shall be marked in kilometres (km). 
5.43.2.3  The  odometer  intended for  school  buses  shall  be  displaye d an  integer  number 
composed of a minimum of 6 digits. 
5.43.3  Speedometer and odometer devises shall meet technical requirem ents and test methods 
according to Standard SASO/FDS 31835 “Road vehicles - Speedomet er and odometer 
devises”. 
 
5.44 Controls, telltales and indicators devices 
5.44.1  The controls shall be available in order for them to be operat ed by the driver. 
5.44.2  The tell-tales and indicators and their identification shall b e located so that they are 
clearly visible to the driver when operating during the day and  night. 
5.44.3  Each school bus shall be equipped with the controls, telltales  and indicators as following: 
1) Master lighting switch; 
2) Headlamp passing beams; 
3) Headlamp high beams; 
4) Headlamp cleaning; 
5) Turn signal indicator; 
6) Hazard warning signal; 
7) Rear fog lamp; 
8) Fuel level; 
9) Engine oil pressure; 
10) Engine coolant temperature; 
11) Electrical charging condition; 
12) Windscreen washing system; 
13) Windscreen washing and wiping system; 
14) Windscreen defrosting and defogging system; 
15) Rear window defrosting and defogging system; 16) Position, side marker; 
17) Safety belt reminder; 
18) Airbag; 
19) Antilock brake system; 
20) Speedometer; 
21) Odometer; 
22) Parking brake; 
23) Horn; 
24) Engine on-board diagnostics; 
25) Air conditioning system; 
26) Heating system; 
27) Low tyre pressure; 
28) Electronic stability control; and 
29) Automatic transmission control position. SASO S TANDAR D SASO/FDS 31827/2020
36 
 5.44.4  Each school bus shall meet the location, identification, color , and illumination 
requirements in Standard SASO/FDS 31836 “Road vehicles - Contro ls, telltales and 
indicators”. (ECE 121:2015 & FMVSS 571.101) 
5.44.5  The identifications of control, indicator, and telltale shall be placed on or near them to 
identify the control, indicator, and telltale. 
5.44.6 Air system pressure gaug e 
Vehicles equipped with air ride suspension shall be supplied wi th an air system pressure gauge. 
 
5.45 Vehicle identification number (VIN)  
5.45.1  The VIN number shall contain 17 characters and shall comply wi th the Saudi Standard 
SASO GSO 1780 
5.45.2  The VIN number shall be readable through the vehicle glazing f rom outside the vehicle 
adjacent to the left windshield pillar of the light duty vehicl es and shall comply with the Saudi 
Standard SASO GSO 1782 5.45.3  The characters of the VIN number shall in all cases be legible , durable and not easily 
altered. 
 
5.46 Speed limiters 
Each school bus shall be provided with a means of limiting the maximum speed so that its speed 
does not exceed 80 km/h, and shall meet the technical requireme nts according to Saudi Standard 
SASO GSO 1625 when tested in accordance SASO GSO 1626. 
 
5.47 Air bags  
5.47.1  The air bag shall be located in suitable position to assist in  preventing the driver’s head 
and chest from impacting the steering wheel or windshield. 
5.47.2  The material used to inflate the bag shall not be toxic and ca use any irritation. 
5.47.3  School buses with GVW less than 3500 kg shall be provided with  air bags to the driver 
and front passenger outboard seat. 
5.47.4  School buses carrying 22 passengers and less shall be provided  with air bags to the driver 
side and the front passenger. 
 
5.48 Transm ission, starter interlock, and transmission braking effect 
5.48.1  Each school bus shall be provided with a transmission, starter  interlock, and transmission 
braking effect that meet the technical requirements according t o Standard SASO/FDS 
31840 “Road vehicles - Transmission shift position sequence, st arter interlock, and 
transmission braking effect” (FMVSS 571.102) 
5.48.2  Automatic transmissions shall have no fewer than three forward  speeds and one reverse 
speed. 
5.48.3  Mechanical shift selectors shall provide a detent between each  gear position when the 
gear selector quadrant and shift selector are not steering-colu mn mounted. 
5.48.4  Automatic transmissions shall have a transmission shifter inte rlock controlled by the 
application of the service brake to prohibit accidental engagem ent of the transmission. 
5.48.5  The force required to operate the throttle shall not exceed 7 kg throughout the full range 
of accelerator pedal travel. 
 SASO S TANDAR D SASO/FDS 31827/2020
37 
 5.49 Air cleaner 
5.49.1  A dry element air cleaner shall be provided. 
5.49.2  All diesel engine air filters shall include a latch-type restr iction indicator that retains the 
maximum restriction developed during operation of the engine, a nd the indicator should include 
a reset control so the indicator can be returned to zero when d esired. 
 
5.50 Suspension syste ms 
5.50.1  The capacity of springs or suspension assemblies shall be comm ensurate with the chassis 
manufacturer’s GVWR. 
5.50.2  Rear leaf springs shall be of a progressive rate or multi-stag e design . 
5.50.3  Front leaf springs shall have a stationary eye at one end and shall be protected by a 
wrapped leaf, in addition to the main leaf. 
 
5.51 Towing attachment points 
5.51.1  Each school bus shall be provided with a front and rear towing  devices (i.e., tow hooks, 
tow eyes, or other designated towing attachment points) to assi st in the retrieval of buses that 
are stuck and/or for towing buses when a wrecker with a “wheel lift” or an “axle lift” is not 
available or cannot be applied to the towed vehicle. 5.51.2  Towing devices shall be attached to the chassis frame either b y the chassis manufacturer 
or in accordance with the chassis manufacturer’s specifications . 
5.51.3  Each towing device shall have a strength rating of 13,500 poun ds each, for a combined 
rating of 27,000 pounds with the force applied in the rearward direction, parallel to the ground, 
and parallel to the longitudinal axis of the chassis frame rail . 
5.51.4  For pulling and lifting purposes, tow hooks are meant to be us ed simultaneously. 
5.51.5  The towing devices shall be mounted such that they do not proj ect forward of the front 
bumper or rearward of the rear bumper. 
Note: Type A buses are exempt from the requirement for front tow hooks or eyes due to built-in crush zones. 
 
5.52 Hinges 
All exterior metal door hinges shall be designed to allow lubri cation to be channeled to the 
center 75% of each hinge loop without disassembly, unless they are constructed of stainless 
steel, brass or non-metallic hinge pins or other designs that p revent corrosion. 
 
5.53 Accele rator control 
The maximum time to return of a school bus throttle to the idle  position when the driver removes 
the actuating force from the accelerator control, or in the eve nt of a severance or disconnection 
in the accelerator control system as shown in Standard SASO/FDS  31838 “Road vehicles 
- Accelerator control systems” (FMVSS 571.124), as following: 
a) 1 second for vehicles of 4536 kilograms or less gross vehicle weight rating (GVWR); and 
b) 2 seconds for vehicles of more than 4536 kilograms gross vehic le weight rating (GVWR). SASO S TANDAR D SASO/FDS 31827/2020
38 
 5.54 Passenge r compartment air conditioning 
5.54.1 General 
5.54.1.1  Each school bus shall be equipped with air conditioning. 
5.54.1.2  Evaporator cases, lines and ducting (as equipped) shall be des igned in such a manner 
that all condensation is effectively drained to the exterior of  the bus below the floor level under 
all conditions of vehicle movement and without leakage on any i nterior portion of the bus. 
5.54.1.3  Evaporators and ducting systems shall be designed and installe d to be free of 
projections or sharp edges. 5.54.1.4   On  school  buses  equipped  with  Type-2  seatbelts  having  anchorages  above  the 
windows, the ducting (if used) shall be placed at a height suff icient to not obstruct occupant 
securement anchorages. 
5.54.1.5  The body may be equipped with insulation, including sidewalls,  roof, firewall, rear, 
inside body bows and plywood or composite floor insulation to r educe thermal transfer. 
5.54.1.6  Electrical generating capacity shall be provided to accommodat e the additional 
electrical demands imposed by the air conditioning system. 
5.54.1.7  Roofs may be painted white t o aid in heat dissipation 
5.54.1.8  Air intake for any evaporator assembly(ies), except for front evaporator of Type A-1, 
shall be equipped with replaceable air filter(s) accessible wit hout disassembly of evaporator 
case. 
5.54.1.9  For all buses (except Type D rear engine transit) equipped wit h a rear evaporator 
assembly, evaporator shall not encroach upon head impact zone, but may occupy an area of less 
than 673 mm from the rear wall and 355 mm from the ceiling. 
5.54.1.10  For Type D rear engine transit buses equipped with a rear evap orator over the 
davenport, the evaporator assembly may not interfere with rear exit window and may not extend 
above the rear seating row. 
5.54.2 
Performanc e 
The installed air conditioning system shall cool the interior o f the bus from 20 to 37 C, under 
the test conditions specified in the item 5.54.3.1, and measure d at three points (minimum) 
located 1.2 m above the floor on the longitudinal centerline of  the bus as following: 
1) One m above the center point of the horizontal driver seat sur face, 
2) At the longitudinal midpoint of the body, and 
3) One m forward of the rear emergency door or, for Type D rear-e ngine buses, One m forward 
of the end of the aisle. 
Note: for the Type A vehicles placement of the rear thermocouple should be centered in the bus over the re ar axle. 
5.54.3 Test Conditions 
5.54.3.1 The following conditions apply to test: 
1) Placing the bus in a room (such as a paint booth) where ambien t temperature can be 
maintained at 37 C; 
2) heat-soaking the bus at 37 C at a point measured two feet hori zontally from the top of the 
windows on both sides of the bus , with windows open for two hou rs; and 
3) closing windows, turning on the air conditioner with the engin e running at 1250 ± 50 RPM, 
and cooling the interior of the bus to 26 C, (standard performa nce) or 20 C (high performance), 
within 30 minutes while maintaining 37 C outside temperature. SASO S TANDAR D SASO/FDS 31827/2020
39 
 5.54.3.2  The manufacturer shall provide test results that show complian ce with standard 
systems. 
 
5.55 Exterior noise level 
5.55.1  Each school bus shall be constructed so that the noise level d oes not exceed 85 dBA 
when measured by the two methods described in GSO technical reg ulation according to Saudi 
Standard SASO GSO 1624 when the bus is moving or stationary. 
5.55.2  The vehicle, its engine and its noise reduction system shall b e so designed, constructed 
and assembled as to enable the vehicle, in normal use, despite the vibration to which it may be 
subjected, to comply with the provisions of this requirements. 
5.55.3  The noise reduction system shall be so designed, constructed a nd assembled as to be able 
to reasonably resist the corrosive action to which it is expose d having regard to the conditions 
of use of the vehicle and the environmental conditions prevaili ng. 
 
5.56 Limits of gaseous pollutant s 
5.56.1 Light-duty unleaded gasoline engines 
5.56.1.1  All school buses with a gross vehicle weight (GVW) of 3500 or less kg shall meet the 
allowable limits of gaseous pollutants and particle mass emitte d to the atmosphere according to 
Saudi Standard SASO GSO 1680 when tested in accordance SASO GSO  1681, SASO GSO 
1682, SASO GSO 1683, SASO GSO 1684 and SASO GSO 1685. 
5.56.1.2  There shall be no gases emission from the crankcase of the sch ool bus to the 
atmosphere. 
5.56.1.3  The evaporative emission emitted from the fuel system shall no t exceed 2.0 grams/test. 
5.56.2 Light-duty diesel engines 
5.56.2.1  All school buses with a gross vehicle weight (GVW) of 3500 or less kg shall meet the 
allowable limits of gaseous pollutants and smoke emitted to the  atmosphere according to Saudi 
Standard SASO GSO 1040 when tested in accordance SASO GSO 1041 and SASO GSO 1042. 
5.56.2.2  There shall be no gases emission from the crankcase of the sch ool bus to the 
atmosphere. 
5.56.3 Heavy-duty diesel engines 
5.56.3.1  All school buses provided with Heavy-duty diesel engines shall  meet the allowable 
limits of gaseous pollutants and smoke emitted to the atmospher e according to Saudi Standard 
SASO GSO 144 when tested in accordance SASO GSO 145 and SASO GS O 146. 
5.56.3.2  The use of defeat device and irrational emissions control stra tegy is not allowed. 
5.56.4 Heavy-duty gasoline engines 
5.56.4.1  All school buses provided with Heavy-duty gasoline engines sha ll meet the exhaust 
emission requirements according to ECE regulations and/or FMVSS  regulations in order for 
SASO/GSO technical regulations to be approved regarding SASO/GS O the allowable limits of 
gaseous pollutants and particle mass emitted to the atmosphere from heavy-duty gasoline 
engines. 5.56.4.2  The carbon monoxide in the exhaust gases at idle speed shall n ot exceed 3.5% by 
volume. 
5.56.4.3  There shall be no gases emission from the crankcase of the sch ool bus  to the 
atmosphere. SASO S TANDAR D SASO/FDS 31827/2020
40 
 6- Safety equipm ent’s 
6.1 General 
6.1.1  Each school bus shall be provided with the tools necessary to dismantle and install the 
wheels so that they are suitable for use according to the type of bus and include the lifting 
machine (jack); its lever and wheel spanner. 
6.1.2  Each school bus shall be provided with a fire extinguisher and  a first aid kit shall be 
located within 2 m of center of the top of the driver’s seat cu shion, regardless of location of the 
driver’s seat. 6.1.3  The 
mechanism for accessing and releasing safety equipment shall not require the removal 
or adjustment of any unrelated object. 
6.1.4  Each school bus shall be provided with two reflector triangles  for use in emergency 
situations and in accordance with Standard(13). 
6.1.5  Each school bus shall be provided with tyre pressure gauge. 
6.2 Fire extingui sher 
6.2.1  All school buses shall be equipped with at least one portable fire extinguisher from dry 
chemical and a rating of at least 2-A:10B-C according to Saudi Standard SASO GSO ISO 7165 
"Firefighting -- Portable fire extinguishers -- Performance and  construction" 
6.2.2  The portable fire extinguisher shall be equipped with a pressu re gauge and shall be 
mounted in a location that is readily accessible to the driver.  
Note: If the fire extinguisher is not in view (e.g., in an enclosed compartment), its location shall be clearly marked. 
6.3 First aid kit 
6.3.1  All school buses shall be provided with first aid kit made of metal or plastic of comparable 
strength at a suitable location and shall be mounted in a locat ion that is readily accessible to the 
driver. 
Note: If the first aid is not in view (e.g., in an enclosed compartment), its location shall be clear ly marked. 
6.3.2  The first aid kit shall contain at least the following items: 
a) one first aid pocket guide; 
b) one record book; 
c) four pairs of non-latex gloves; 
d) 150 individually wrapped 25 × 75 mm adhesive dressings; 
e) eight 50 mm compress dressings; f) six 100 mm compress dress ings; g) two gauze eye pads; 
h) one eye shield; 
i) three four-ply gauze dressings, a minimum of 914 × 914 mm in  size; 
j) two 50 mm × 5.5 m gauze bandages; 
k) one packet of 25 mm × 4.6 m adhesive tape; 
l) six triangular bandages; 
m) one 70 × 610 mm rolled metal splint; 
n) one pair of sliver tweezers; 
o) one pair of 15 cm scissors; and 
p) twelve 50 mm safety pins. 
 
 
 
(13) Follow the standard 49 CFR 571.125 or ECE 27 until the Saudi st andard is adopted . SASO S TANDAR D SASO/FDS 31827/2020
41 
 7- Information of vehicle 
7.1 The manufacturer shall be mounted a conformity label to the ed ge or latch post on the 
driver’s door of each school buses. 
7.2 The conformity label shall meet the following requirements: 
7.2.1  It shall be made of material resistant to deterioration. 
7.2.2  It shall be permanently affixed in a manner that that is diffi cult to remove without 
damaging it. 
7.2.3  It shall be shown the information in both Arabic and English l anguages, and the height of 
the letters shall not be less th an 2.4 mm, and be in a clearly legible manner can be read easily: 
7.2.3.1 Name of manufacturer and country of manufacture (or assemble). 
7.2.3.2  Year and month of production. 
7.2.3.3  Maximum gross vehicle weight (GVW) in kilograms. 
7.2.3.4  Maximum gross axle weight rating (GAWR) for each axle, in kilo grams. 
7.2.3.5  Designation the recommended tire size from the vehicle's manuf acturer. 
7.2.3.6  Number of passengers. 
7.2.3.7  Weight of the passenger load. 
7.2.3.8  The statement “This school buses complies with all Saudi stand ard for vehicles that 
were issued up to the date of manufacture”. 
7.3 If the school bus is equipped with a navigation system, all ge ographic data and maps shall 
be in Arabic with the ability to convert them into English (Ara bic & English), and the voice 
guidance systems shall be in Arabic with the ability to convert  it into English (Arabic & 
English). 
7.4 An All instructions indicated on the driver's monitor/display shall be available in Arabic 
and English 
 
8- Owner’s manual (Operating Instr uctions) 
Each school bus shall be equipped with Owner’s manual in Arabic  and English including the 
following information: 
8.1 The technical specifications of the school bus. 
8.2 Instructions relating to the operation of the school bus. 
8.3 Instructions relating to the periodic maintenance. 
8.4 Technical instructions about the recommended tyre designation,  indicating inflation 
pressure and replacement method. 
8.5 The maximum speed limit, maximum torque and maximum power at . ... rpm. SASO S TANDAR D SASO/FDS 31827/2020
42 
 9 - Ide ntification 
9.1 Each school bus shall be provided with the following stickers:  
9.1.1  The word "SCHOOL BUS" shall be displayed in both Arabic and English on the front  
and back of the bus, and its letters are in black color. 
The letters shall meet the following requirements: 
a) It shall be at least 200 mm high, with a minimum stroke with o f 32 mm. 
b) It shall be placed as high as possible without reducing its vi sibility. 
c) It shall be placed above the windshield and rear window and no t more than 25 off the vertical. 
d) It shall be in approximately the same horizontal plane as the red signal lamps and within 200 
mm of the vertical plane of the warning lamps. 
9.1.2  The words “DO NOT PASS WHEN RED LIGHTS FLASHING” shall be displayed in 
both Arabic and English on the rear of the bus, and its letters  are in black color. 
The letters shall meet the following requirements: 
a) the lettering shall be at least 75 mm, but not more than 125 m m, high; and 
b) the stroke width of the lettering shall be at least one-sixth the height of the letters. 
9.1.3  The type of fuel used by the school bus shall be indicated on the body, immediately in 25 
mm lettering adjacent to the filler pipe. 
9.1.4  The words “DO NOT PARK WITHIN 3 M OF THIS SIDE” shall be displ ayed in both 
Arabic and English on the mobility aid entrance as a warning po ster, and its letters are in black 
color, and the letter height shall not be less than 25 mm. 
9.1.5  The words “CAUTION  – STAND CLEAR”  shall be displayed in both  Arabic and 
English on the mobility aid entrance as a warning poster, and i ts letters are in black color, and 
the letter height shall not be less than 25 mm. 
9.1.6  The word "BATTERIES" shall be indicated on the battery compartment door in 50 mm 
lettering; SASO S TANDAR D SASO/FDS 31827/2020
43 
 10- School bus requirements for persons with special health care needs 
10.1 General 
School buses equipped with wheelchair accessible shall meet the  requirements of Clauses          
4 to 9, in addition to the following requirements: 
10.2 International symbol of wheelchair 
The international symbol of wheelchair (see Figure (2)) shall m eet the following requirements: 
a) Minimum size of 100 x 100 mm. 
b) Placed on the exterior front and rear of the bus in a location  that is visible to traffic. 
10.3 Mobility aid entrance 
10.3.1 Location 
10.3.1.1  An accessible bus mobility aid entrance shall be located on th e right side of the bus. 
10.3.1.2  The mobility aid entrance shall be located immediately rearwar d of the service entrance 
door. 
10.3.2 Width and height 
a) The mobility aid entrance shall be equipped with an installed lift. 
b) A minimum of 760 mm width and 1400 mm height shall be the clea r opening of a mobility 
aid entrance. 
10.3.3 Automated illumination  
School buses shall be equipped with a light, which automaticall y operates when the mobility 
aid entrance open. The light shall illuminate the lift platform . 
10.4 Emergency exit door  
10.4.1  School buses equipped with mobility aid entrance shall have em ergency door exits 
located on a different wall of the bus than the mobility aid en trance. 
10.4.2  The emergency exit door shall have a minimum width of 760 mm. 
10.5 Aisle width 
The aisle width of all school buses equipped to accommodate a m obility aid shall have a 
minimum of 760 mm between fixed vehicle structures leading from  any mobility aid position 
to at least one emergency exit door. 
10.6 Mobility aids 
10.6.1 Space requirements 
10.6.1.1 Floor spac e 
a) The minimum floor space requirements for each mobility aid sha ll be 685 x 1220 mm. 
b) The 1220 mm length shall be parallel to the vehicle’s longitud inal centerline (see Figure (3)). 
c) A maximum overlap of 150 mm of mobility aid positions or ambul atory seating in the 
longitudinal direction may be used. 
10.6.1.2 Fixed vehicle structures 
There shall be no fixed structures within a mobility aid positi ons, except for mobility aid 
securement and occupant restraint system (MASOR), school bus se ats, or school bus barriers 
within the clear zone shown in Figure (4). SASO S TANDAR D SASO/FDS 31827/2020
44 
 10.6.2 Securement 
10.6.2.1 Securement devices 
All mobility aid devices shall meet the requirements of Standar d(14). 
10.6.2.2  Securement anchorage  points 
The anchorage points for the mobility aid securement system sha ll be separated from each other 
by a minimum center-to-center distance of 350 mm as shown in Fi gure (3) and shall withstand 
a forward and rearward static loading of 15.7 kN applied in acc ordance with Figure (5). 
Note: The applied load of 15.7 kN is compatible with Standard(15)(substituting for the seat a mobility aid having a 
minimum test mass of 80 kg. 
10.6.3 Mobility aid occupant restraint 
10.6.3.1 Seat belts 
a) A type 2 seat belt assembly shall be provided at each outboard  mobility aid position. 
b) A type 1 and 2 seat belt assembly shall be provided at each in board mobility aid position. 
c) All seat belt assemblies shall meet the technical requirements  of Standard(16).  
d) Type 2 occupant restraint systems shall meet the requirements of Standard(14).  
Note: 
a) See Standard(16) of the MVSR for definitions type 1 and 2 seat belt assemblies. 
b) Scooter-type mobility aids should be transported only in a position where a type 2 se at belt is provided. 
10.6.3.2 Occupant restraint anchorage points 
a) Anchorage points in an occupant restraint system shall meet th e strength requirements of 
Standard(17). 
b) The upper torso anchorage points shall eb located within the z one shown in Figure (6). 
10.6.4 Simultaneous loading 
If a mobility aid securement and occupant restraint systems sha re common anchorage points, 
the loading requirements of Clauses 10.6.2.2 and 10.6.3.2 shall  be met simultaneously. 
10.7 Lifts  
Vehicle lifts and installations shall comply with the requireme nts of Standards Standard(18). 
 
            
 
(14) Follow the standard CAN/CSA-Z605 or equivalent until the Saudi standard is adopted . 
(15) Follow the standard FMVSS 207 until the Saudi standard is adopt ed.  
(16) Follow the standard FMVSS 209 until the Saudi standard is adopt ed.  
(17) Follow the standard FMVSS 210 until the Saudi standard is adopt ed. 
(18) Follow the standard FMVSS 403 & 404 or equivalent until the Sau di standard is adopted . SASO S TANDAR D SASO/FDS 31827/2020
45 
 10.8 Caution labels for entrances and lifts 
10.8.1 Caution label for the mobility aid entrance 
The following wording shall appear adjacent to or on the mobili ty aid entrance in Arabic and 
English: 
 
 
DO NOT PARK WITHIN 3 M OF THIS SIDE  & (  ﺣ ﺿ اﻟ ﻣ3 أﻣ)  
 
 
10.8.2 Caution label for the lift 
The following wording shall appear adjacent or on the lift in A rabic and English: 
 
 
CAUTION – STAND CLEAR & (  ﺗ  - Ǻ ʃɾ ) 
 
The cautionary notice shall be clearly visible when viewing the  vehicle from outside, in the 
general proximity of the lift entrance. 
10.8.3 Appe arance 
The lettering in the labels specified in Clauses 10.8.1 and 10. 8.2 shall be 
a) At least 25 mm high. 
b) In a color that contrasts with the background. 
c) Readily visible. 
Pictograms in accordance with Standard(19) may be used in conjunction the written labels. 
10.9 Seating for ambulatory passe ngers 
On lift-equipped school buses with ambulatory seating, seat fra mes shall be equipped type 1 or 
type 2 seat belt assemblies (as defined in Standard(17)). 
 
 
 
 
 
  
 
  
 
  
 
  
 
  
 
  
 
  
 
 
(19) Follow the standard SAE J2402 until the Saudi standard is adopt ed. SASO S TANDAR D SASO/FDS 31827/2020
46 
  
 
 
 
 
Figure (2) – International symbol of wheelchair SASO S TANDAR D SASO/FDS 31827/2020
47 
  
All dimensions are in millimetres (i nches) 
 
 
 
 
 
 
Notes: 
1) Anchor zones are located equidistant with respect to the mobility reference plane, e.g., 175 mm either side of 
the line. 
 
 
Figure (3) – Top view of the maximum mobility aid outline SASO S TANDAR D SASO/FDS 31827/2020
48 
  
 
 
 
All dimensions are in millimetres (i nches) 
 
 
  
 
 
* FCZ (front clear zone) = 650 mm with upper-torso restraint = 950 mm with only pelvic restraint. 
Notes: 
1) The rear clear zone is measured from the rearmost point on an occupant’s head.  
2) The front clear zone is measured from the frontmost point on an occupant’s head. 
3) Seated head height (HHT) ranges from about 1200 mm for a small adult female to about 1550 mm for a tall 
adult male. 
4) Both pelvic and upper-torso belts should be used (this is strongly recommended) 
 
 
 
Figure (4) – Clear zone around a mobility aid position SASO S TANDAR D SASO/FDS 31827/2020
49 
  
 
  
 
 
 
Figure (5) – Loading of anchorage points in a mobility aid securement system SASO S TANDAR D SASO/FDS 31827/2020
50 
 
 
 
  
All dimensions are in millimetres (i nches) 
 
 
  
 
  
 
  
 
  
 
  
 
  
 
  
 
  
 
  
 
  
 
  
 
  
 
 
 
Notes: 
1) SH is the shoulder height from the floor. 
It is 775 mm for a six-year-old child ATD (anthropometric test dummy), or 1100 mm for a 50th percentile male 
ATD, seated in a mobility aid. 
The front clear zone is measured from the frontmost point on an occupant’s head. 
2) NHB is the half-neck breadth. 
It is 50 mm for a six-year-old child ATD, or 75 mm for a 50th percentile male ATD, seated in a mobility aid. 
3) HSB is the half shoulder breadth. 
It is 130 mm for a six-year-old child ATD, or 200 mm for a 50th percentile male ATD, seated in a mobility aid. 
 
 
Figure (6) – Loading of anchorage points for an upper torso restrain belt SASO S TANDAR D SASO/FDS 31827/2020
51 
  
Annex (A) 
(Normative ) 
 
 
Roof hatch performance test 
 
 
 
A.1 The test shall be conducted under the following conditions: 
a) The school bus shall be on a flat horizontal surface; and 
b) The temperature inside and outside shall be maintained between  20 and 30 for 4 h 
immediately preceding the test and during the test. 
 
 
A.2 An increasing force shall be applied to the head form shown in  figure (A.1) to cause at a 
velocity of 51 mm/min from a point inside the bus that is at th e center of the roof hatch plane 
in a direction that is outward and perpendicular to the undistu rbed surface of the hatch until one 
of the following occurs: 
a) the force at the point of application equals 3100 N; 
b) The roof hatch opens; or 
c) The inner surface of the hatch at the center has moved perpend icularly to undisturbed surface 
of the hatch a distance equal to the length of the smallest cho rd along the surface of the hatch 
passing through the center divided by 4. SASO S TANDAR D SASO/FDS 31827/2020
52 
  
 
All dimensions are in millimetres (i nches) 
 
 
 
 
 
 
 
  
 
Legend: 
A = 6.35 ± 0.63 mm synthetic underlayer, with 1720 ± 170 kPa te nsile strength and 50 ± 10 % elongation. 
B = Napa goat skin, wet chamois, or 0.76 ± 0.07 mm synthetic sk in, all with 6900 ± 350 kPa tensile strength and 
100 ± 5 % elongation. 
 
 
 
Figure (A.1) – Head-form SASO S TANDAR D SASO/FDS 31827/2020
53 
 Annex (B) 
(Normative ) 
 
 
Side Intrusion Test 
 
 
 
B.1 Procedures 
B.1.1  The complete body structure, or a representative seven-body se ction mock up with seats 
installed, shall be load-tested at a location 610 ± 50 mm above  the floor line, with a maximum 
254 mm diameter cylinder, 1220 mm long, mounted in a horizontal  plane. 
B.1.2  The cylinder shall be placed as close as practical to the mid- point of the tested structure, 
spanning two internal vertical structural members. 
B.1.3  The cylinder shall be statically loaded to the required force of curb weight or 9090 kg, 
whichever is less, in a horizontal plane with the load applied from the exterior toward the 
interior of the test structure. 
 
 
B.2 Acceptance criteria 
B.2.1  When the minimum load has been applied, the penetration of the  loading cylinder into 
the passenger compartment shall not exceed 10 inches from its o riginal point of contact. 
B.2.2  There can be no separation of lapped panels or construction jo ints. 
B.2.3  Punctures, tears or breaks in the external panels are acceptab le but are not permitted on 
any adjacent interior panel. 54SASO STANDAR D  SASO/FDS 31827/202 0 
  
Bibliography  
 
[1] National congress on school transportation (2015  Edition ). 
[2] CAN /CSA-D250-16 "School buses".